Fruit color is an important breeding trait of mango (Mangifera indica L.), that directly affects it's appearance quality and commodity value. The mango cultivars, 'Jinhuang' ('JH') and 'Guifei' ('GF'), exhibit a peel color transition from green to yellow or red during ripening. In contrast, the cultivar 'Guiqi' ('GQ') retains its green peel and sweet fragrance even at full ripeness, exhibiting a stay-green phenotype. Here, we identified two Mangifera indica Stay-Green genes (MiSGR1 and MiSGR2) from these cultivars and investigate their roles in peel color development. The expression level of MiSGR1 was markedly lower in 'GQ' than in 'JH' and 'GF', whereas MiSGR2 showed no significant expression difference. Sequencing analysis identified a single-base substitution (G→A) at position 641 in the open reading frame of MiSGR2 from 'GQ', which introduced a premature stop codon (designated MiSGR2STOP) and truncated 43 amino acids relative to MiSGR2 from 'GF' and 'JH'. Over-expression assay in heterologous system demonstrated that both MiSGR1 and MiSGR2 catalyzed chlorophyll degradation, whereas MiSGR2STOP lacked this activity. Yeast two-hybrid and BiFC analyses further confirmed that MiSGR1 and MiSGR2 interacted with protein MiPPH1, while MiSGR2STOP failed to do so. These results suggest that the single-nucleotide mutation in MiSGR2 disrupts its activity in chlorophyll degradation and interaction with MiPPH1, leading to the stay-green phenotype of 'GQ'. Our findings provide new insight into the molecular regulation of peel color in mango and a genetic basis for breeding cultivars with improved visual and nutritional quality.

Multiple transmembrane proteins perform functions such as immune stress and signal transduction, and we cloned and characterized an immune-functional, transmembrane protein MiRPH1, from mango. Expression analysis showed that MiRPH1 has tissue-specific characteristics and is induced by pathogens and phytohormones. Under pathogenic infection, overexpression of MiRPH1 could increase the accumulation of salicylic acid (SA), catalase (CAT), and peroxidase (POD) in plants, reduces the biomass of pathogenic fungus, and upregulates the expression of multiple defense-related genes, thereby enhancing plant disease resistance. It is speculated that MiRPH1, as a transmembrane protein that exercises immune function, can enhance the resistance of mangoes to pathogenic fungus.

IntroductionThe color of Clausena lansium L. Skeels cv. Jixin fruit peel is brown (BP), while the mutant cv. Zijin had purple fruit peels (PP). The coloration of the peels was attributed to significant differences in chlorophyll, carotenoid, and anthocyanin content between BP and PP.MethodsThis study investigates the biosynthetic metabolic activities in the brown and purple peels of Clausena lansium L. Skeels using metabolomics and transcriptomics. It aims to identify metabolic pathways and differentially expressed genes related to flavonoids and anthocyanins biosynthesis.ResultsThe PP (purple peel) has higher levels of a-carotene and b-carotene but lower levels of chlorophyll a, chlorophyll b, and lutein compared to BP. Zeaxanthin was absent from both peels, suggesting that the b-carotene hydroxylase enzyme is not active. Both peels contain delphinidin-based (Dp) and cyanidin-based (Cy) anthocyanins, but not pelargonidin-based (Pg). The total anthocyanin content and the Dp/Cy ratio are higher in PP than in BP. The delphinidin, cyanidin, and mallow derivatives in the PP were significantly higher than in the BP. The increase of total anthocyanin content and Dp/Cy ratio may be the main reason for the peel color changing from brown to purple. The significant increase of F3H expression in purple peels suggested a higher efficiency of catalyzing the conversion of naringenin into dihydroflavonols in the PP, leading to the higher content of total anthocyanin. Despite the significant increase of FLS expression in PP, the contents of kaempferol, quercetin, and myricetin significantly decreased, suggesting that the increase of FLS expression did not lead to an increase in flavonol biosynthesis.DiscussionThe competition between F3’H and F3’5’H may determine the ratio of Dp/Cy, the higher levels of F3’H, F3’5’H, and UFGT expression, lead to the increase accumulation of total anthocyanin and Dp/Cy in PP. The deficiency of Pg in both peels resulted from the substrate specificity of the DFR enzyme. The research also describes the transition in color from BP to PP and details of the biosynthetic pathways for carotenoids and anthocyanins, elucidating the molecular processes underlying anthocyanin production.

Plants cope with the biotic stress caused by pathogen infection through complex resistance mechanisms. Here, we identified a secreted laccase Cglac8 from Colletotrichum gloeosporioides and confirmed its involvement in C. gloeosporioides infection of mango (Mangifera indica) plants, as well as its ability to activate the host's innate immune mechanism. Cglac8 interacted with MiLRR-RLP1 and Mi14-3-3-D1 as demonstrated by yeast two-hybrid, bimolecular fluorescence complementation and pull-down assays. The interacting proteins MiLRR-RLP1 and Mi14-3-3-D1 positively regulate mango resistance to C. gloeosporioides by promoting the reactive oxygen species burst and biosynthesis of phytohormones. When Cglac8, MiLRR-RLP1 and Mi14-3-3-D1 proteins were overexpressed together in mango, the resistance of mango to C. gloeosporioides was significantly enhanced. Our findings reveal a new defence mechanism of host plants against C. gloeosporioides, providing a theoretical basis for disease-resistant molecular breeding. The dual role of secretory laccase Cglac8 may reflect a balancing mechanism in host-pathogen co-evolution.

Background/Objectives: Mango, which is known as the “King of Tropical Fruits”, is an evergreen plant belonging to the Anacardiaceae family. It belongs to the genus Mangifera, which comprises 69 species of plants found in tropical and subtropical regions, including India, Indonesia, the Malay Peninsula, Thailand, and South China. However, research on the structural information of complete chloroplast genomes of Mangifera is limited. Methods: The rapid advancement of high-throughput sequencing technology enables the acquisition of the entire chloroplast (cp) genome sequence, providing a molecular foundation for phylogenetic research. This work sequenced the chloroplast genomes of six Mangifera samples, performed a comparative analysis of the cp genomes, and investigated the evolutionary relationships within the Mangifera genus. Results: All six Mangifera samples showed a single circular molecule with a quadripartite structure, ranging from 157,604 bp to 158,889 bp in length. The number of RNA editing sites ranged from 60 to 61, with ndhB exhibiting the highest number of RNA editing sites across all species. Seven genes—namely, atpB, cemA, clpP, ndhD, petB, petD, and ycf15—exhibited a Ka/Ks value > 1, suggesting they may be under positive selection. Phylogenetic analysis revealed that Mangifera siamensis showed a close relationship between Mangifera indica and Mangifera sylvatica. Conclusions: Our comprehensive analysis of the whole cp genomes of the five Mangifera species offers significant insights regarding their phylogenetic reconstruction. Moreover, it elucidates the evolutionary processes of the cp genome within the Mangifera genus.

Mango, as a major tropical fruit, is deeply loved by consumers due to its unique color and flavor. Fruit color is one of the important quality traits that determine its nutritional and commercial value. There are significant differences in the peel color of mango germplasm resources. However, the reason for the color difference in fruits is still unclear. In this study, we selected 43 representative mango varieties from the National Mango Germplasm Resources Nursery. Through the evaluation of germplasm resources fruit peels of 43 mango varieties, combined with transcriptomics and metabolomics, it was found that flavonoids play a decisive role in the color changes of mango peel. Overexpression of MiMYB33 can alter the color of tomato fruits by promoting an increase in flavonoid content. This study provides important theoretical basis for the subsequent research on mango fruit color and the cultivation of mango varieties that meet market demand.

Caffeic acid O-methyltransferase (COMT) participates in various physiological activities in plants, such as positive responses to abiotic stresses and the signal transduction of phytohormones. In this study, 18 COMT genes were identified in the chromosome-level reference genome of mango, named MiCOMTs. A phylogenetic tree containing nine groups (I-IX) was constructed based on the amino acid sequences of the 71 COMT proteins from seven species. The phylogenetic tree indicated that the members of the MiCOMTs could be divided into four groups. Quantitative real-time PCR showed that all MiCOMT genes have particularly high expression levels during flowering. The expression levels of MiCOMTs were different under abiotic and biotic stresses, including salt and stimulated drought stresses, ABA and SA treatment, as well as Xanthomonas campestris pv. mangiferaeindicae and Colletotrichum gloeosporioides infection, respectively. Among them, the expression level of MiCOMT1 was significantly up-regulated at 6–72 h after salt and stimulated drought stresses. The results of gene function analysis via the transient overexpression of the MiCOMT1 gene in Nicotiana benthamiana showed that the MiCOMT1 gene can promote the accumulation of ABA and MeJA, and improve the salt tolerance of mango. These results are beneficial to future researchers aiming to understand the biological functions and molecular mechanisms of MiCOMT genes.

"热品 16 号"是从"海顿杧"开放授粉的后代株系中选育出的杧果新品种. 2021 年通过全国热带作物品种审定委员会审定,2023 年入选农业农村部主导品种.

叶绿素降解是果实色泽形成过程中一个主要的影响因素.脱镁叶绿素酶(pheophytinase,PPH)是叶绿素降解代谢的关键酶.本研究提取杧果果皮总RNA,采用RACE方法,克隆得到一个脱镁叶绿素酶基因,并对其进行了初步的生物信息学分析.序列分析表明MiPPH基因cDNA序列全长1 267 bp,开放阅读框为1 113 bp,可编码370个氨基酸,分子量为41.73 kD,等电点为5.22.使用NCBI上的Conserved domains分析MiPPH蛋白结构域,结果显示MiPPH含有PLN02578、Abhydrolase_1共2个结构域,其中PLN02578为保守域,其他物种PPH也都含有这个水解酶(Hydrolase)保守域,说明PPH蛋白有高度的保守性.通过BLAST上其他植物的氨基酸序列进行相似性比对,利用DNAMAN生成的系统进化树发现杧果MiPPH蛋白序列和与同为漆树科的开心果的PPH蛋白序列相似度较高,亲缘关系较近.利用定量PCR技术对不同品种中的MiPPH基因表达量进行分析,发现绿色'桂七'品种表达量最高,而黄色'金煌'品种表达量最低,黄色'金煌'品种和红色'贵妃'品种表达量相差不大.本试验成功构建pCAMBIA2300-GFP-MiPPH植物表达载体,通过农杆菌介导的烟草瞬时表达,亚细胞定位MiPPH主要定位于细胞核.本试验为后续进行PPH基因的功能验证提供试验基础.

Mangifera indica L. cv. Keitt is a cold-stress fruit plant native to China's drought river valley. Chilling stress affects productivity. Understanding the mechanisms of chilling stress is important to increasing chilling resistance in mango. Leaves of Keitti were subjected to 4 °C for 0, 3, 6, and 9 h for RNA-Seq-based transcriptome analysis, respectively. The chlorophyll content, carotenoid content, catalase, and peroxidase activities significantly increased during 9 h. The leaves responded to the stress by enhancing photosynthetic pigment content and antioxidant enzyme activity. After 3 h of chilling, 410 genes were differentially expressed. WRKY70 and PLD1 were significantly up-regulated after 9 h. Compared to 9 and 0 h, there were 1123 DEG. The DEGs are enriched in hormonal signal transduction, secondary metabolites, and the abiotic stress response. Similarly, the transcriptional factor families including NCED2, MYB73, and HLH162 up-regulated. The study will promote research on the development of chill-resistant mangoes.

Carotenoids are essential and beneficial substances for both plant and human health. Identifying the regulatory network of these pigments is necessary for improving fruit quality and commodity value. In this study, we performed integrative analyses of transcriptome data from two different type fruits, ripening peel color at green ('Neelum' mango) and red ('Irwin' mango). Specifically, we found that MiMYB10 transcription level was highly associated with mango peel color. Further, silencing MiMYB10 homologous gene in tomato fruits resulted in lower carotenoid and anthocyanin content. Electrophoretic mobility shift assays and dual-luciferase clarified that MiMYB10 regulates the carotenoid biosynthesis gene MiPDS (phytoene desaturase gene) in a direct manner. On the other hand, MiMYB10 activates the expression of carotenoid biosynthesis genes (PSY, Z-ISO, CRTISO, LCYE) and chlorophyll degradation gene (SGR1), promoting the accumulation of carotenoid, accelerating chlorophyll degradation, and controlling peel color. In summary, this study identified important roles of MiMYB10 in pigment regulatory and provided new options for breeding strategies aiming to improve fruit quality.

Mangoes (Mangifera indica L.) are an important kind of perennial fruit tree, but their biochemical testing method and transformation technology were insufficient and had not been rigorously explored. The protoplast technology is an excellent method for creating a rapid and effective tool for transient expression and transformation assays, particularly in plants that lack an Agrobacterium-mediated plant transformation system. This study optimized the conditions of the protoplast isolation and transformation system, which can provide a lot of help in the gene expression regulation study of mango. The most beneficial protoplast isolation conditions were 150 mg/mL of cellulase R-10 and 180 mg/mL of macerozyme R-10 in the digestion solution at pH 5.6 and 12 h of digestion time. The 0.16 M and 0.08 M mannitol in wash solution (WI) and suspension for counting (MMG), respectively, were optimal for the protoplast isolation yield. The isolated leaf protoplasts (~5.4 × 105 cells/10 mL) were transfected for 30 min mediated by 40% calcium-chloride-based polyethylene glycol (PEG)-4000-CaCl2, from which 84.38% of the protoplasts were transformed. About 0.08 M and 0.12 M of mannitol concentration in MMG and transfection solutions, respectively, were optimal for protoplast viability. Under the florescence signal, GFP was seen in the transformed protoplasts. This showed that the target gene was successfully induced into the protoplast and that it can be transcribed and translated. Experimental results in this paper show that our high-efficiency protoplast isolation and PEG-mediated transformation protocols can provide excellent new methods for creating a rapid and effective tool for the molecular mechanism study of mangoes.

多酚氧化酶(Polyphenol oxidase,PPO)是引起水果褐变的关键酶.为了研究芒果果实中PPO基因的功能,本试验采用RACE方法从'贵妃'芒果果实中克隆得到了 1个PPO基因,该基因cDNA序列全长为1930bp,开放阅读框为1782bp,编码593个氨基酸.芒果PPO基因编码的多酚氧化酶属于亲水性蛋白质,分子重量为66.82KD,等电点为6.95,不含跨膜结构和信号肽,为非分泌蛋白,包含Tyrosinase、PPO1_DWL和PPO1_KFDV保守结构域.芒果PPO蛋白的二级结构无规则卷曲、β-折叠和α-螺旋占比分别为63.58％、22.60％和13.83％,三级结构与模板6els.1.A一致性达70.94％,可能与 C2H2 and C2HC zinc fingers superfamily protein(TT1),Multidrug resistance protein,mate family(TT12)和Autoinhibited H(+)-ATPase isoform 10(AHA10)等存在相互作用.聚类分析表明该蛋白与开心果、橄榄、克莱门柚和甜橙等植物的亲缘关系较近.通过qRT-PCR分析,芒果PPO基因主要在'桂七'果皮中表达量较高,而在'贵妃'果皮中表达量较低.该基因的克隆及其功能的研究对芒果抗酶促褐变品种的培育以及分子改良具有重大意义.

The biosynthesis of anthocyanins and proanthocyanidins (PAs), components of two main flavonoids in plants, is regulated by environmental factors such as light. We previously found that bagging significantly repressed the biosynthesis of anthocyanins in red 'Ruby' mango fruit peel, but induced the accumulation of PAs. However, the molecular mechanism remains unclear. In the current study, transcriptome sequencing was used for screening the essential genes responsible for the opposite accumulation pattern of anthocyanins and PAs by bagging treatment. According to weighted gene co-expression network analysis (WGCNA), structural genes and transcription factors highly positively correlated to anthocyanins and PAs were identified. One flavanone 3-hydroxylase (F3H) and seven structural genes, including one chalcone synthase (CHS), one flavonoid 3'-hydroxylase (F3'H), one anthocyanidin synthesis (ANS), three leucoanthocyanidin reductase (LARs), and one UDP glucose: flavonoid 3-O-glucosyltransferase (UFGT), are crucial for anthocyanin and PA biosynthesis, respectively. In addition to MYB and bHLH, ERF, C2H2, HD-ZIP, and NAC are important transcription factors that participate in the regulation of anthocyanin and PA biosynthesis in 'Ruby' mango fruit peel by bagging treatment. Our results are helpful for revealing the transcription regulation mechanism of light-regulated mango anthocyanin and PA biosynthesis, developing new technologies for inducing flavonoid biosynthesis in mangos, and breeding mango cultivars containing high concentrations of flavonoids.

Mango (Mangifera indica L.) is a widely appreciated tropical fruit for its rich color and nutrition. However, knowledge on the molecular basis of color variation is limited. Here, we studied HY3 (yellowish-white pulp) and YX4 (yellow pulp), reaped with 24 h gap from the standard harvesting time. The carotenoids and total flavonoids increased with the advance of harvest time (YX4 > HY34). Transcriptome sequencing showed that higher expressions of the core carotenoid biosynthesis genes and flavonoid biosynthesis genes are correlated to their respective contents. The endogenous indole-3-acetic acid and jasmonic acid contents decreased but abscisic acid and ethylene contents increased with an increase in harvesting time (YX4 > HY34). Similar trends were observed for the corresponding genes. Our results indicate that the color differences are related to carotenoid and flavonoid contents, which in turn are influenced by phytohormone accumulation and signaling.

Introduction Flavonoids are important water soluble secondary metabolites in plants, and light is one of the most essential environmental factors regulating flavonoids biosynthesis. In the previous study, we found bagging treatment significantly inhibited the accumulation of flavonols and anthocyanins but promoted the proanthocyanidins accumulation in the fruit peel of mango ( Mangifera indica L.) cultivar ‘Sensation’, while the relevant molecular mechanism is still unknown. Methods In this study, RNA-seq was conducted to identify the key pathways and genes involved in the light-regulated flavonoids biosynthesis in mango peel. Results By weighted gene co-expression network analysis (WGCNA), 16 flavonoids biosynthetic genes were crucial for different flavonoids compositions biosynthesis under bagging treatment in mango. The higher expression level of LAR ( mango026327 ) in bagged samples might be the reason why light inhibits proanthocyanidins accumulation in mango peel. The reported MYB positively regulating anthocyanins biosynthesis in mango, MiMYB1 , has also been identified by WGCNA in this study. Apart from MYB and bHLH, ERF, WRKY and bZIP were the three most important transcription factors (TFs) involved in the light-regulated flavonoids biosynthesis in mango, with both activators and repressors. Surprisingly, two HY5 transcripts, which are usually induced by light, showed higher expression level in bagged samples. Discussion Our results provide new insights of the regulatory effect of light on the flavonoids biosynthesis in mango fruit peel.

YABBY is a specific transcription factor gene family in plants. It has the typical N-terminal C2C2-type zinc-finger domain and the C-terminal YABBY conservative structure domain, which play an important role in the development of the leaves and floral organs. The YABBY gene family directs leaf polarity in mango, playing an important role in maintaining species specificity. In this study, a total of seven YABBY genes were identified in the mango (Mangifera indica) genome. The seven YABBY family members possessed both typical C2C2 and YABBY domains. A phylogenetic tree was constructed based on the amino acid sequences of the 42 YABBY proteins of mango, Arabidopsis, apple, grape, and peach. The phylogenetic tree indicated that the members of the mango YABBY family could be divided into three subfamilies, including CRC, YAB5, and YAB3. Quantitative real-time PCR showed that the transcription levels of the MiYABBYs were significantly different under biotic and abiotic stresses. The transcription level of MiYABBY7 was significantly down-regulated at 0–72 h after Xanthomonas campestris pv. mangiferaeindicae infection, methyl jasmonate and salicylic acid stresses. The MiYABBY1 transcription level was significantly down-regulated at 0–72 h after Colletotrichum gloeosporioides infection. MiYABBYs were expressed specifically in different leaves and fruit, and MiYABBY6 was significantly up-regulated during leaf and fruit development. However, MiYABBY5 showed a contrary transcriptional pattern during leaf and fruit development. This is first report on the mango YABBY gene family at the genome-wide level. These results will be beneficial for understanding the biological functions and molecular mechanisms of YABBY genes.

Phytoene desaturase (PDS) affects the synthesis of carotenoids. It is a key gene in the carotenoids biosynthesis pathway. In order to study the function of PDS gene from mango fruits, the phytoene dehydrogenase ( PDS ) gene of ‘Guifei’ mango fruit was obtained with RACE methods. The full-length cDNA sequence of the gene is 1 820 bp, open reading frame is 1 650 bp, encoding 549 amino acids, the molecular weight is 61.34 KD, and the isoelectric point is 6.78. It was cluster analysis found that the mango PDS protein had a close relationship with grapefruit, cantaloupe, and papaya. Its amino acid composition is mainly alanine (ALa), leucine (Leu), valine (Val), and so on. Expression of PDS gene in different varieties by PCR showed: the high expression of the red ‘Guifei’ varieties and the expression of green mango varieties with low volume. Prediction of the domain, tertiary structure, and interaction protein of its protein, found to contain phytoene-desat, PLNO2487 superfamily, and other domains. The use of the STRING database found PDS interacted with proteins such as PSY, ZDS, and CRTISO. This research will be valuable for understanding the molecular mechanism of gene regulation in carotenoid biosynthesis and can be served as the basis for the metabolic engineering of mango.

为科学评价黄皮种质果实品质奠定基础,采用主成分分析和聚类分析的方法,以23份黄皮种质资源的成熟果实为试材,测定单果重、果实纵径、果实横径、果形指数、可食率、可溶性固形物、蛋白质、VC含量、总酸、可溶性糖、糖酸比11项品质指标,从中筛选出具有代表性的黄皮品质评价指标,并对23份黄皮种质进行聚类.结果表明,单果重、VC、蛋白质、可溶性糖、总酸和糖酸比的变异系数均在20％以上,其中黄皮果实的糖酸比变异系数最大,高达108.57％,不同黄皮种质间营养成分的含量差异大,具有丰富的遗传信息和多样性;而果实横径、果形指数的变异系数均在10％以下,果形指数的变异系数最小,仅6.98％,黄皮外观形状、大小遗传比较稳定、改良空间较小;23份黄皮种质的各品质指标之间存在显著或极显著的相关性;将数据标准化处理后,进行主成分分析,提取出4个具有代表性的主成分,累计方差贡献率达到85.41％;通过计算得到第1～4主成分因子得分和品质指标的综合得分,其中第1、2主成分在黄皮品质综合评价中起到关键作用,综合评价得分最高的为A3,得分最低的为G1;对黄皮种质资源的品质影响较大且相对独立的有单果重、果形指数、可食率、可溶性糖、总酸和糖酸比这6个指标;将6个具有代表性的品质指标的数据标准化处理后进行系统聚类分析,在欧氏距离15处,可得到4大类群,第I大类群有A3和Y-2,果实大、可食率较高、糖酸比高,风味偏甜,品质优良,第II大类群有X1、Y-1、G2和B1,果实较大,形状多样,可食率高,可溶性糖和糖酸比较低,品质较差,第III大类群包括300-1、J2、300-2、9-3、H1、A1、Z1、A2、N-3这9份黄皮种质,其果实大小偏低,可食率较高,酸甜适中,第IV类群包括A5、N-1、H2、A6、T1、G1、J1、J3这8份种质,其果小,可食率低,可溶性糖较低,总酸较高,糖酸比极低,口感较差.

DELLA蛋白是赤霉素(GA)代谢通路中的受体因子,参与了数种环境信号、激素信号的系统反应.本研究采用同源克隆的手段,参考NCBI登录的'阿方索'芒果的基因组数据,克隆了'贵妃'芒果的DELLA-GAI基因.其全长cDNA序列长2 120 bp,包含一个1 719 bp的开放阅读框(ORF),编码572个氨基酸,蛋白分子量为62.9 kD,等电点为5.10.由系统进化树分析可知,可可、榴莲、番木瓜、木薯等作物与该基因编码的蛋白聚为一类.经互作蛋白分析发现,芒果DELLA-GAI可能与GID1B、GID1C、SLY1、PIF4、JAZ1、GA3OX1等蛋白存在相互作用.启动子结构分析发现,该启动子主要含有MYB响应元件、光响应元件、植物抗病相关元件、MYC响应元件、MYB识别位点以及脱落酸和水杨酸响应元件.通过检测DELLA-GAI基因在'贵妃'芒果果实不同发育阶段的表达情况发现,其在果实成熟期和完全成熟期表达量比较高,而在幼果期的表达量比较低.该基因及其启动子的研究与分析为探究'贵妃'芒果果实色泽及其抗逆境调控机制提供了条件.