Promoters are crucial upstream regulatory sequences of genes that control their expression. Among them, promoters of reproductive tissue play a key role in the precise expression of genes at specific developmental stages. Earlier, the function of the BIN gene has been investigated in Arabidopsis thaliana. In this study, we have characterised promoter of this gene in detail. We cloned a 2959 bp AtBIN promoter and expressed the GUS gene with it in A. thaliana. Transgenic plants showed GUS expression in the developing microspore and tapetum of the anther. No detectable GUS activity in vegetative tissues and siliques under tested condition indicated exclusive expression from the promoter. Progressive deletion of 751, 1499, and 2230 bp DNA from upstream did not change the specificity of the promoter, although the expression was reduced. Interestingly, the 729 bp variant possessed all essential cis-regulatory elements necessary for male reproductive tissue-specific gene expression. De novo motif analysis of a 729 bp promoter with 50 co-expressed genes identified five putative motifs associated with the regulatory expression network in anther development. The findings validated the expression of AtBIN promoter in male reproductive tissues and established no expression in other parts of plant under tested condition. It also highlights the development a smaller version of AtBIN promoter by deleting 75
The demand for Arundo donax seedlings has increased owing to its high economic value. Tissue culture method based on clustered bud proliferation can efficiently produce high-quality A. donax seedlings. However, the proliferation coefficient of buds is affected by plant hormones. This study aimed to investigate the effects of 6-benzylaminopurine (6-BA) and 3-indolebutyric acid (IBA) co-treatment on the proliferation activity of A. donax tissue culture and explore the underlying mechanism using integrated morphological, physiological, and transcriptomic analyses. The proliferation coefficients significantly varied with the different supplementation of 6-BA and IBA in culture media. New axillary buds were derived from the base of the inoculated bud with a distichous alternate pattern or a fascicled pattern. Treatment with exogenous 1.0–5.0 mg/L 6-BA and 1.0 mg/L IBA significantly decreased endogenous 3-indoleacetic acid (IAA) and abscisic acid (ABA) contents and significantly increased trans-zeatin (tZ) and gibberellin A3 (GA3) contents in the clustered buds. In addition, tZ content and tZ/IAA and tZ/ABA ratios were closely related to the proliferation coefficients. Transcriptomic analysis identified 242 differentially expressed genes involved in regulating proliferation coefficient by influencing the transcriptional regulation, photosynthesis, protein autoprocessing and secretion, substance biosynthesis and metabolism, plant hormone biosynthesis and signal transduction. Meanwhile, cluster-6016.49727 (UDP-glucosyltransferase 73 C) enriched in zeatin biosynthesis, cluster-6016.20238 (transcription factor TGA) and cluster-6016.51459 (glutamine synthetase 2) enriched in plant hormone signal transduction showed a strong correlation with the proliferation coefficient, and may play an essential role in the determination of the proliferation ability of clustered buds in A. donax tissue culture. Overall, this study provides a theoretical basis for the development of highly efficient strategies for producing A. donax seedlings through tissue culture.
Most studies on tomato seed stress have looked at whole seeds, but the way different parts of the seed respond to radiation, and how that connects to observable traits through gene networks, hasn’t really been explored much. This work looked at how ‘Micro-Tom’ tomato seeds react when specific embryonic regions are hit with precise radiation. A scanning electron microscope was used to irradiate five distinct parts the whole seed, the cotyledon and plumule, the embryonic axis, the radicle, and the embryo for varying lengths of time, ranging from 0 to 150 s. The results showed that radiating any of these parts slowed down germination and shifted the leaf’s physio-chemical profile, though the radicle turned out to be the most sensitive spot. Peroxidase activity seemed to act as a kind of central hub in the overall radiation response, tying together germination rates, seedling growth, physio-chemical changes, and what was happening at the transcript level. Looking deeper into the transcriptomic data, radiating the radicle set off a cascade of gene expression changes, with transcription factors playing a key role in steering those radiation-responsive networks. By combining weighted gene co-expression network analysis with the phenotypic data, 12 core genes linked to radiation adaptation were pinned down, including SolyMTch11g325300, SolyMTch11g314230, and SolyMTch01g003120. In practice, these findings could offer some useful pointers for making radiation treatments more efficient and for pushing precision radiation techniques further along in breeding programs.
Eclipta prostrata (L.) L., a medicinal plant belongs to the Asteraceae family and known for its bioactive secondary metabolites (SMs), exhibits dynamic metabolic regulation across tissues, developmental stages, and under stress conditions. This study investigates the distribution of wedelolactone (WDL), demethylwedelolactone (DW), luteolin, luteolin-7-glucoside, apigenin, naringenin and nicotinic acid to understand their biosynthetic patterns. Developmental stage and tissue specific analysis indicates that most SMs accumulate predominantly in shoot tissues, except for DW, which is enriched in roots. Flavonoids such as luteolin, luteolin-7-glucoside, and apigenin, are most abundant in shoot at vegetative stage, while WDL and nicotinic acid accumulate in shoot mainly during reproductive stage and DW in root at vegetative stages. To explore the impact of SA, MJ, wound and abiotic stress stimuli on the distribution of SMs in root and shoot tissues, we examined stress-induced metabolite accumulation at various time points. Our findings revealed that abiotic stresses, particularly temperature fluctuations (cold and heat), increase SM accumulation, suggesting that temperature variations are associated with altered metabolite levels in both tissues. MJ, SA, and wound stress also alter SM levels, whereas, wounding, and methyl jasmonate (MJ) treatment amplifies their accumulation in their respective tissue where they were accumulated mainly, suggesting root or shoot specific role in stress-induced metabolic reprogramming and reinforcing their involvement in plant defense. These findings provide insights into the patterns of SM distribution and stress-responsive accumulation, offering a foundation for optimizing bioactive compound production. Understanding these dynamic variations can aid in the development of strategies for sustainable utilization and enhancement of E. prostrata’s medicinal potential.
Seed hardness is an important trait affecting fruit texture, consumer preference, and processing suitability in guava (Psidium guajava L.). The present study investigated the structural, biochemical, metabolomic, and transcriptional basis of seed hardness using six guava genotypes with contrasting seed hardness. Seed hardness measurements revealed a clear separation between hard and soft seeded genotypes, with CIW-5, G-6, and Kamsari exhibiting greater mechanical resistance than Arka Mridula, Purple Local, and H-104. Biochemical analysis showed consistently higher lignin accumulation in hard seeded genotypes, with increased soluble, insoluble, and total lignin fractions indicating enhanced seed coat lignification. Acid hydrolysis followed by HRLC-MS analysis revealed relatively higher accumulation of phenylpropanoid and lignin associated metabolites in hard seeds, together with a higher relative abundance ratio of selected syringyl and guaiacyl associated metabolites. These results indicate differences in lignin-associated metabolism between hard and soft seeded genotypes. As syringyl-rich lignin forms predominantly linear β-O-4 linkages whereas guaiacyl-rich lignin forms more condensed carbon–carbon linkages, this shift is consistent with a more compact and mechanically resistant seed coat wall. Transcriptome analysis identified 2,588 differentially expressed genes (DEGs) between pooled hard and soft seeded genotypes and 13,258 DEGs between CIW-5 and Purple Local, including numerous genes associated with phenylpropanoid metabolism, lignin biosynthesis, and secondary cell wall formation. Functional enrichment analysis highlighted pathways related to cell wall organization and phenylpropanoid biosynthesis. Developmental expression profiling showed that most lignin biosynthesis genes exhibited maximum expression at 65 days after flowering (DAF), indicating that this stage is closely associated with seed coat hardening. Scanning electron microscopy and ImageJ based quantitative analysis indicated a comparatively compact seed coat structure in hard seeds and a more porous architecture in soft seeds. These findings demonstrate a strong association between lignin mediated seed coat reinforcement and seed hardness in guava, and identify candidate genes together with a defined developmental window at 65 DAF that provide a practical entry point for the selection of soft seeded genotypes in guava improvement programmes.
