Auxin transport through the abscission zone (AZ) is crucial for preventing organ abscission in plants; however, the regulatory mechanisms involved remain poorly understood. Here, we demonstrate that exogenous auxin application alone fully inhibits abscission triggered by litchi (Litchi chinensis Sonn.) fruitlet removal, which depletes auxin in the AZ. Following fruitlet removal, we observed sequential and significant alterations in 7 biological processes within the AZ, including the transient suppression of auxin signaling and activation of ethylene and abscisic acid signaling, followed by the increased production of reactive oxygen species, reduced carbohydrate content, and ultimately, the induction of programmed cell death and cell wall remodeling (CWR). Moreover, we identified 34 transcription factors as potential key regulators and constructed transcriptional regulatory networks involved in auxin depletion-induced abscission. Notably, we characterized LcMYB62 as a positive regulator of abscission, likely functioning by transactivating genes associated with CWR. We further showed that the transcription factor AUXIN RESPONSE FACTOR 5 (LcARF5) binds to and activates LcMYB62, suggesting a LcARF5-LcMYB62-CWR transcriptional regulatory cascade in litchi fruitlet abscission. Overall, our findings provide a comprehensive overview of the gene regulatory network governing auxin-mediated fruitlet abscission in litchi, providing insights into the mechanisms by which auxin depletion in the AZ triggers this process.

Volatile terpenoids are pivotal to fruit aroma and serve as the major aroma-donating volatiles in litchi aril, yet their biosynthetic mechanisms remain largely unknown. By profiling 24 litchi cultivars, we identified 14 key terpenoids (e.g., caryophyllene, geraniol, and d-limonene) that classify cultivars into light and strong aroma groups. A genome-wide screening identified 46 LcTPS genes, with LcTPS39 showing the highest aril expression and functioning as a caryophyllene synthase. Transcriptomic and promoter analyses revealed a strong correlation between transcription factors LcCDF3 and LcTPS39. Subsequent in vitro and in vivo assays confirmed that LcCDF3 directly binds and activates the LcTPS39 promoter. Furthermore, overexpression of LcCDF3 in litchi callus and tomato fruits significantly enhanced caryophyllene production. Collectively, this study comprehensively characterizes litchi aril volatile terpenoids and elucidates a novel LcCDF3-LcTPS39 regulatory module controlling caryophyllene biosynthesis, offering valuable insights for the genetic improvement of fruit aroma.

Organ abscission is a core developmental process that allows plants to optimize resource allocation, maximize reproductive fitness, and respond to environmental cues. In agricultural systems, however, premature fruit abscission can severely reduce yield. Here, we investigate premature fruit drop in litchi and identify the hexokinase homolog LcHXK1 as a nonglycolytic hexose sensor that suppresses abscission by activating a pedicel lignification program. LcHXK1 physically associates with and phosphorylates the WRKY transcription factor LcWRKY42, a modification that enhances its stability and transcriptional activity in inducing laccase and peroxidase genes required for lignin polymerization, promoting lignin deposition and reinforcing the pedicel to prevent organ detachment. Over expression of LcHXK1 or LcWRKY42 in litchi callus and in Arabidopsis elevates lignin content, increases laccase and peroxidase activities, and delays organ abscission, revealing a conserved sugar-responsive pathway. LcWRKY42 also upregulates LcHXK1, forming a positive feedback loop that amplifies hexose signaling. Together, these findings define a sugar-sensing regulatory module that couples carbon status to pedicel lignification, providing a mechanistic framework for improving fruit retention in crops.

Fatty acid-derived volatile organic compounds (VOCs), especially C6 and C9 aldehydes and alcohols, are vital contributors to the fresh aroma of fruits. However, the specific volatiles responsible for this freshness and their biosynthetic regulatory mechanisms remain poorly characterized in litchi (Litchi chinensis Sonn.). In this study, we systematically characterized the VOC profiles of 24 representative litchi cultivars and identified four critical compounds-trans,cis-2,6-nonadien-1-ol, 1-hexanol, (E)-6-nonenal, and (E)-2-hexen-1-ol-as primary determinants of fresh-aroma variation. Weighted gene co-expression network analysis of the transcriptomic data, corroborated by RT-qPCR, revealed a strong positive correlation between the expression of LcLOX7 and the abundance of these key fresh-aroma volatiles. Functional characterization via LcLOX7 overexpression in litchi callus and tomato fruits validated its pivotal role in enhancing the biosynthesis of fatty acid-derived VOCs, specifically C9 volatiles. Subsequent in vivo and in vitro assays confirmed the direct transcriptional activation of LcLOX7 by two transcription factors (TF), LcARF17 and LcRAP2-4. The expression patterns of these TFs correlated with the accumulation of key fresh-aroma volatiles across different litchi cultivars and paralleled LcLOX7 expression during fruit ripening. Moreover, overexpression and silencing of LcARF17 or LcRAP2-4 in litchi callus validated their regulatory function in promoting C9 volatile synthesis. Our findings collectively support a regulatory model wherein the LcARF17/LcRAP2-4-LcLOX7 module orchestrates the biosynthesis of fresh aroma in litchi fruit. Notably, this study provides the first evidence that ARF transcription factor participates in the formation of fresh fruit aroma, thereby offering novel insights for the molecular breeding of flavor quality in fruit crops.

【Objective】3,5,6-trichloro-2-pyridinyloxyacetic acid(3,5,6-TPA)has been proven to have a positive effect on the enlargement and maturation of litchi fruits. However, previous studies have been limited to phenotypic observations, lacking in research on the mechanisms by which it regulates fruit size and maturation. This study used the high-quality late-maturing litchi variety Xianjinfeng as the experimental material to explore the regulatory mechanisms by whole-tree spraying of 40 mg·L-13,5,6-TPA on litchi fruit growth and development, aiming to provide a scientific basis for its rational application in litchi production.【Methods】Sixteen-year-old Xianjinfeng litchi trees grafted onto Feizixiao rootstocks were used as experimental materials. Six trees with relatively consistent vigor were selected, with three trees sprayed with 40 mg·L-13,5,6-TPA and the other three sprayed with water as controls. The spraying was conducted five weeks after flowering(when the young fruit was about 1 g), until the leaf surface was dripping wet, with a volume of 8 L per tree. Fifteen branches were randomly selected from each treatment for tagging and fruit drop rate statistics. If fruit splitting occurred, the fruits were removed after counting and 20 fruits were randomly selected from each treatment for tagging to measure their transverse and longitudinal diameters for dynamic fruit development analysis. Eight mature leaves of the same age and position were selected from the external canopy of each tree and tagged, and their net photosynthetic rate was measured using a CIRAS-3 portable photosynthesis system (PP system, USA)every three days between 9:00—11:00 a.m., before and after treatment, until photosynthetic damage was restored. Fruit samples were collected once a week, with 30 fruits per sample. The pericarp, pulp, and seeds were separated, frozen in liquid nitrogen, and stored in a-80℃ freezer for the determination and analysis of major physiological indices of the fruit. The fruit quality was finally measured at harvest.【Results】Spraying with 3,5,6-TPA significantly enlarged the Xianjinfeng litchi fruit. The average fruit weight of the treated group reached 25.0 g, while that of the control was only 22.9 g, representing a 9.2% increase in the treated group compared to the control. The proportion of first-grade fruit in the treated group increased by 137.5% compared to the control, while the proportion of substandard fruit decreased by 128.3%. The treatment also advanced fruit maturation by one week but did not alter the final coloration of the pericarp after maturation. It had no significant effect on the fruit soluble solids, titratable acid, solid-acid ratio, edible rate, or rate of sunken seeds. Spraying with 3,5,6-TPA inhibited fruit drop in the first four weeks after treatment. However, some fruits on the panicles stopped growing and the pericarp turned yellow. These developmentally arrested fruits began to drop from the third week, and by harvest, the cumulative fruit drop rate in the treated group was higher than that in the control, although the difference was not significant. Spraying with 3,5,6-TPA temporarily induced photosynthetic damage in litchi leaves within 10 days after treatment, which then returned to normal. Spraying with 3,5,6-TPA significantly increased the sucrose content in the aril 2-3 weeks after treatment, as well as the contents of fructose, glucose, and total sugar, with no significant differences at harvest. Spraying with 3,5,6-TPA altered the activity of key enzymes in aril sucrose metabolism, significantly increasing acid invertase activity in the third week after treatment, neutral invertase activity in the second week, with no significant difference in sucrose synthase activity, and increased sucrose phosphate synthase activity before the fourth week, which then fell below the control. Foliar application of 3,5,6-TPA advanced the peak of endogenous IAA during fruit ripening and accelerated the subsequent decline by 1 week relative to the control, while it increased the ABA content in various tissues of the fruit. The potential reasons for the promotion of fruit enlargement by 3,5,6-TPA treatment include: (1)Briefly inhibiting the net photosynthetic rate of litchi leaves, causing some fruits to be abortted in the early developmental stage and then drop, which had a thinning effect; (2)Increasing the endogenous IAA content in the pericarp, aril, and seeds during the early stages of fruit development; (3)Enhancing the activities of cell wall invertase, acid invertase, neutral invertase, and sucrose phosphate synthase, thereby promoting sugar accumulation and fruit development. The potential reasons for the accelerated fruit maturation include: (1)Increasing the endogenous ABA content in the pericarp, aril, and seeds during fruit development; (2)Promoting the early decline of endogenous IAA content in the pericarp and aril during fruit maturation.【Conclusion】Compared with the control,3,5,6-TPA can temporarily inhibit the net photosynthetic rate of litchi leaves without significantly affecting the intrinsic quality of Xianjinfeng litchi. It can also alter the activity of related metabolic enzymes in the aril, promote sugar accumulation in the early stages of fruit development, and regulate the endogenous IAA and ABA contents in various fruit tissues, thereby effectively increasing fruit size and the rate of high-quality fruit, and promoting early fruit maturation.

Rice stem internal structure is a critical micro-phenotype influencing lodging resistance and yield; however, its analysis remains constrained by labor-intensive manual methods. Here, we present a publicly available dataset of 686 rice stem cross-sections, with 21,027 large vascular bundles (LVBs) and 19,342 small vascular bundles (SVBs) manually annotated. Five deep learning architectures were systematically evaluated, among which UNet-VGG16 achieved the best performance with a mean intersection over union (mIoU) of 87.4% (82.49% for LVBs and 74.41% for SVBs). An improved model, UNet-ECA-Bio, further raised mIoU to 89.32% and SVB IoU to 78.97% by integrating Efficient Channel Attention (ECA) and biologically informed class weighting using an image-level dataset. Leveraging these high-accuracy phenotypic predictions, genome-wide association studies (GWAS) indicated concordance between annotated and predicted traits, with SNP overlap rates of 96% (LVB count: 1,217/1,262), 43% (SVB count: 6/14), 98% (stem area: 122/124), and 100% (cavity area: 3/3) at −log10(p) ≥ 6. Meanwhile, compared with manual annotation (estimated 10–30 minutes per image), the proposed approach processed all 686 images within 10 minutes, representing a >600-fold increase in throughput. We further developed a user-friendly software tool, “Rice_Stem_Pre_V1.1.exe,” for automated phenotyping of 14 stem traits, providing a cost-effective platform for genetic studies of lodging resistance and yield improvement.

The IDA/IDL (INFLORESCENCE DEFICIENT IN ABSCISSION or like) peptides are conserved core components of the plant organ abscission machinery. However, the transcriptional networks governing IDA/IDL expression and their upstream regulators remain poorly understood. We previously identified LcIDL1 as a potential key positive regulator of litchi (Litchi chinensis Sonn.) fruitlet abscission. In the present study, yeast one-hybrid screening revealed that LcIDL1 promoter is directly bound by the transcription factor BRASSINAZOLE RESISTANT2 (LcBZR2), an essential constituent of the brassinosteroid (BR) signaling pathway functioning as a negative regulator of fruitlet abscission. Furthermore, we further demonstrated that LcBZR2 exerts trancriptional repression on LcIDL1 by specifically binding to its promoter. Consistently, proLcIDL1:GUS signals in the abscission zone (AZ) were suppressed in a 35S:LcBZR2 background. To test the functional conservation of this regulatory module, we examined Arabidopsis and found that the BR-insensitive mutant bri1 exhibits significantly accelerated floral organ abscission, elevated AtIDA expression in the floral AZ, and altered AZ cellular morphology. Moreover, AtBZR1 was also shown to suppress AtIDA transcription by specifically binding to its promoter. Collectively, these findings reveal functionally conserved BZR-IDA/IDL regulatory module in both litchi and Arabidopsis, which is critical for mediating organ abscission.

Reactive oxygen species (ROS) are pivotal in regulating plant organ abscission. The buildup of ROS in the fruitlet abscission zone (FAZ) actively triggers the abscission of litchi fruitlets. In this chapter, we present a simple method to measure intracellular ROS levels in the FAZ of litchi using 2,7-dichlorodi-hydrofluorescein diacetate (DCFH-DA). Litchi FAZ samples are transverse sectioned and then incubated with a 50 μM DCFH-DA solution at room temperature for 1 h. DCF fluorescence can be visualized using a laser scanning confocal microscope, and the fluorescence intensity is then analyzed with ImageJ software.

Bergamotene, a key sesquiterpene compound, is crucial for defining the fruity aroma. However, the precise regulatory mechanisms governing its biosynthesis have been largely elusive. In this study, we elucidated that the DOF transcription factor LcDOF5.8 plays a central role in the biosynthesis of α-bergamotene by directly enhancing the expression of the terpene synthase gene LcTPSbms in litchi fruit. Our findings revealed that the concentration of α-bergamotene varies significantly among four distinct litchi cultivars: ‘Guanyinlv’, ‘Bingli’, ‘Guiwei’ and ‘Nuomici’. Notably, a strong correlation was observed between the expression level of LcTPSbms and the content level of α-bergamotene across these cultivars. Furthermore, both in vitro and in vivo catalytic assays confirmed that LcTPSbms is capable of catalyzing the synthesis of α-bergamotene. Importantly, electrophoretic mobility shift assays (EMSA) and Dual-LUC assays demonstrated that LcTPSbms is positively regulated by LcDOF5.8. Silencing LcDOF5.8 in litchi aril resulted in decreased LcTPSbms expression, whereas transient overexpression of LcDOF5.8 led to a significant upregulation of LcTPSbms and a concomitant increase in α-bergamotene biosynthesis. In summary, our research uncovers a regulatory module involving LcDOF5.8 and LcTPSbms that plays a critical role in the biosynthesis of α-bergamotene, offering valuable insights into the molecular mechanisms underlying the fruity aroma of litchi fruit.

Cold can be a tough challenge for rice cultivation, impacting its growth and overall productivity. The Cys2His2 (C2H2) zinc finger (ZF) genes are essential for plants’ responses to abiotic stress. In this study, we identified 99 OsC2H2 genes within the Oryza sativa japonica genome, detailing their gene structure, conserved C2H2-ZF domains, and motif compositions for the first time. We also examined the temporal expression patterns of these genes under cold, heat, drought, flooding, and salt stress. Interestingly, we found that OsC2H2.35 was upregulated during cold stress, and CRISPR/Cas9 editing of this gene enhances rice cold tolerance in seedlings. RNA-seq results showed that OsC2H2.35 negatively regulates several COR genes, including DEHYDRATION-RESPONSIVE ELEMENT BINDING FACTORS 1 s (OsDREB1A, OsDREB1B, and OsDREB1C). Specifically, OsC2H2.35 can directly bind to the promoters of OsDREB1A and OsDREB1C. Osc2h2.35 greatly enhances cold tolerance while preserving all essential agronomic traits, making it a valuable gene target for the genetic improvement of rice.

Aroma is a crucial factor influencing the flavor quality and economic value of longan fruits. This study employed a mapping population consisting of 98 F1 progeny of ‘Shixia × Xiangcui’ (exhibiting broad segregation in fruit aroma trait) and their parents. We performed the SNP genotyping through whole-genome resequencing to construct a high-density linkage map, followed by QTL mapping and candidate gene screening for aroma trait. We obtained a total of 554.9 Gbp of sequencing data, with an average depth of approximately 15× for the parents and 12× for the progeny. Three types of SNP markers (lm×ll, nn×np, and hk×hk) were developed, totaling 317 877. After merging with a 100 kb sliding window, 6 134 Bin markers were generated. A first high-density Bin map was constructed, comprising 15 linkage groups with 3 517 Bin markers (containing 264 385 SNPs), covering a total map length of 1 666.79 cM. The average marker interval was 0.48 cM, with 99.18% of gaps being less than 5 cM. Collinearity analysis confirmed the high quality of the map. Fifty-six QTLs were mapped for 9 aroma-related traits, including (E)-2-hexenal, ethyl acetate, ethyl butyrate, ethyl crotonate, (E)-2-hexenoate, ethanol, linalool, ocimene, and total ester content. These QTLs explained 19.8%–51.0% of the phenotypic variation rates and were distributed across 11 linkage groups, with two QTL-rich regions on LG7 and LG8. Seven pleiotropic QTLs were detected. By analyzing the expression patterns of 1 535 annotated genes within the mapped intervals, six candidate genes potentially regulating the synthesis of ester characteristic aroma compounds were identified: aldo-keto reductase AKRs, acetolactate synthase small subunit ALS2, ACC oxidase ACO1-1, and transcription factors bHLH122, AGL103, and bZip1. This work provides novel insights into the fruit aroma formation, and facilitates breeding efforts to improve quality in longan and potentially other fruit crops.

Cytokinins play crucial roles in regulating the flower bud differentiation in fruit trees. However, the molecular mechanisms by which cytokinins promote flowering in plants are largely unknown. The litchi (Litchi chinensis Sonn.) is a typical subtropical fruit tree that suffers from severe alternate fruiting due to unstable flowering. Here, we developed a novel alternate-fruiting management, which can ensure 100% flowering of the on-year trees, while the off-year trees hardly flower at all. The abundance of two types of cytokinins (tZR, iPR) and LcFT1 expression in the leaves of on-year trees were continuously increased throughout the period of floral bud physiological differentiation. In contrast, these corresponding indicators in off-year trees were maintained at a significantly lower level. Exogenous application of 40 mg/kg 6-BA significantly promoted flowering and increased LcFT1 expression level in the leaves of the off-year trees. LcIPT3, encoding a pivotal rate-limiting enzyme in cytokinin biosynthesis, was identified as the key gene determining the differences in cytokinin levels between on-year trees and off-year trees. Interestingly, we discovered that both LcIPT3 and LcFT1 are directly activated by LcARR11, a type-B cytokinin response factor, as demonstrated through both in vitro and in vivo assays. Furthermore, ectopic expression of LcARR11 in Arabidopsis resulted in elevated IPT expression and cytokinin content, alongside increased FT expression and earlier flowering. Collectively, our findings suggest that cytokinin-mediated promotion of flowering in litchi might be orchestrated by LcARR11, which could promote floral bud physiological differentiation by activating both LcIPT3 and LcFT1.

BACKGROUND:Plant stem structural characteristics are crucial factors determining plant lodging resistance, while high throughput methods for rapid surveys of these traits are still lacking in sorghum. RESULTS:Among 103 sorghum accessions, two kinds of stem powders (dry and water-washed) were subject to visible and near-infrared spectra acquisition, and 16 models (combinations) for stem structural characteristics were generated, revealing that the support vector machine regression model has significant positive effects on the prediction of stem structural characteristics while powder type and pretreatment of spectra has minor effects on the prediction of stem structural characteristics. In addition, we found that stem structure characteristics were positively correlated with agronomic traits but negatively correlated with lodging index which is the criterion that negatively accounts for plant lodging resistance. CONCLUSION:This study for the first time provided a precise and high throughput method for the prediction of sorghum stem structural characteristics based on spectra, which could facilitate the improvement of lodging resistance in crop breeding.

Longan is an exotic tropical fruit crop and exhibits off-season flowering induced by potassium chlorate (KClO3), though the molecular mechanisms remain unclear. We assembled a high-quality, 441.5 Mb genome of variety 'Shixia', with a contig N50 at 28.1 Mb, 29, 325 protein-coding genes, 26 telomeres and 15 centromeres. Comparative genomic analysis with lychee revealed structural variations potentially driving gene family expansions related to flavone biosynthesis and disease resistance. Transcriptomic profiling showed that natural flowering appears to be primarily regulated by photoperiod, vernalisation and autonomous pathways, while KClO3-induced flowering may preferentially activate the gibberellin pathway at 5 days after treatment (DAT) and autonomous pathways at 10 DAT, involving putative repression of DlDDF1, DlFLCs and DlSVPs, and up-regulation of DlWRKY75_2. In the perpetual-flowering variety 'Sijimi', elevated expression of photoperiod genes, such as DlCOR28, DlCOR27, DlADO3, DlPRR5, DlGI and DlJMJ30, may explain its perpetual blooming. Overexpression of DlDDF1 in Arabidopsis delayed flowering, partially reversed by KClO3 through an increase in bioactive GA4. Together, KClO3-induced flowering likely involves oxidative stress response and gibberellin signalling via DlDDF1 repression, while natural flowering relies on seasonal cues. These results lay the foundation for longan genetic improvement.

Although there is increasing evidence suggesting that DNA methylation regulates seed development, the underlying mechanisms remain poorly understood. Therefore, we aimed to shed light on this by conducting whole-genome bisulfite sequencing using seeds from the large-seeded cultivar 'HZ' and the abortive-seeded cultivar 'NMC'. Our analysis revealed that the 'HZ' seeds exhibited a hypermethylation level compared to the 'NMC' seeds. Furthermore, we found that the genes associated with differentially methylated regions (DMRs) and differentially expressed genes (DEGs) were mainly enriched in the reactive oxygen species (ROS) metabolic pathway. To investigate this further, we conducted nitroblue tetrazolium (NBT) and 2,7-Dichlorodihydrofluorescein (DCF) staining, which demonstrated a significantly higher amount of ROS in the 'NMC' seeds compared to the 'HZ' seeds. Moreover, we identified that the gene LcGPX6, involved in ROS scavenging, exhibited hypermethylation levels and parallelly lower expression levels in 'NMC' seeds compared to 'HZ' seeds. Interestingly, the ectopic expression of LcGPX6 in Arabidopsis enhanced ROS scavenging and resulted in lower seed production. Together, we suggest that DNA methylation-mediated ROS production plays a significant role in seed development in litchi, during which hypermethylation levels of LcGPX6 might repress its expression, resulting in the accumulation of excessive ROS and ultimately leading to seed abortion.

From an evolutionary perspective, fruit abscission is an intelligent regulatory mechanism by which fruit trees adapt to their environment and ensure offspring. However, from an agricultural production standpoint, unwanted fruit abscission can cause significant loss in fruit yield and economic value. Therefore, investigating the mechanisms of fruit abscission has always been an important focus in the field of plant research. Acquiring a thorough comprehension of the underlying mechanisms responsible for fruit abscission is highly valuable for enhancing fruit crop breeding and optimizing harvesting practices. In this review, we focus on fruit abscission, particularly discussing the nature of abscission cues within the abscising fruit, how these signals are generated and transmitted, and how the abscission zone cells perceive and respond to these signals in woody fruit crops.

Litchi(Litchi chinensis Sonn.)is a well-known tropical and sub-tropical woody fruit that originated from southern China(Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be divided into three distinct groups:large-seeded cultivars,small(abortive)-seeded cultivars and par-tial abortive-seeded cultivars.Seedless or the reduction in seed size due to embryo abortion is a desirable trait in fruit trees as it directly influences the texture and economic value of fleshy fruits,making small(abortive)-seeded litchi cultivars the most preferred.However,in current production practices,there is no efficient method available to induce or promote high seed abortion in litchi fruit.Therefore,understanding the stenospermy mechanisms of litchi seed development is of great significance for improving agricultural practices and managing genetic resources.

The gene regulatory networks that govern seed development are complex, yet very little is known about the genes and processes that are controlled by DNA methylation. Here, we performed single-base resolution DNA methylome analysis and found that CHH methylation increased significantly throughout seed development in litchi. Based on the association analysis of differentially methylated regions and weighted gene co-expression network analysis (WGCNA), 46 genes were identified as essential DNA methylation-regulated candidate genes involved in litchi seed development, including LcSR45, a homolog of the serine/arginine-rich (SR) splicing regulator SR45. LcSR45 is predominately expressed in the funicle, embryo, and seed integument, and displayed increased CHH methylation in the promoter during seed development. Notably, silencing of LcSR45 in a seed-aborted litchi cultivar significantly improved normal seed development, whereas the ectopic expression of LcSR45 in Arabidopsis caused seed abortion. Furthermore, LcSR45-dependent alternative splicing events were found to regulate genes involved in seed development. Together, our findings demonstrate that LcSR45 is hypermethylated, and plays a detrimental role in litchi seed development, indicating a global increase in DNA methylation at this stage.

[This corrects the article DOI: 10.3389/fpls.2021.802016.].