BITS Faculty Publications
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1867
Browse
3 results
Search Results
Item Role of phytohormones in regulating agronomically important seed traits in crop plants(Elsevier, 2023) Sharma, RitaSeed development is a complex process that commences after double fertilization. Both forward and reverse genetic studies have revealed the critical roles of phytohormones in regulating seed development and the associated agronomic traits. The growing evidence points to the complex interactions among underlying genetic pathways due to hormone cross talk or shared signaling components. Moving forward to deconvolute these complex interactions requires an in-depth understanding of the genes regulating individual hormone pathways. Here, we summarize the multifaceted roles of key genes regulating biosynthesis and signaling of plant hormones, and the broad spectrum of mechanisms underpinning hormone action during seed development. The gain- and loss-of-function phenotypes associated with agronomically important seed traits, namely, seed size, weight, shape, number, longevity, and dormancy, provide compelling evidence for the plant hormones as crucial metabolic engineering targets to optimize seed traits in crop plants.Item Functional delineation of rice MADS29 reveals its role in embryo and endosperm development by affecting hormone homeostasis(OUP, 2013) Sharma, RitaRice MADS29 has recently been reported to cause programmed cell death of maternal tissues, the nucellus, and the nucellar projection during early stages of seed development. However, analyses involving OsMADS29 protein expression domains and characterization of OsMADS29 gain-of-function and knockdown phenotypes revealed novel aspects of its function in maintaining hormone homeostasis, which may have a role in the development of embryo and plastid differentiation and starch filling in endosperm cells. The MADS29 transcripts accumulated to high levels soon after fertilization; however, protein accumulation was found to be delayed by at least 4 days. Immunolocalization studies revealed that the protein accumulated initially in the dorsal-vascular trace and the outer layers of endosperm, and subsequently in the embryo and aleurone and subaleurone layers of the endosperm. Ectopic expression of MADS29 resulted in a severely dwarfed phenotype, exhibiting elevated levels of cytokinin, thereby suggesting that cytokinin biosynthesis pathway could be one of the major targets of OsMADS29. Overexpression of OsMADS29 in heterologous BY2 cells was found to mimic the effects of exogenous application of cytokinins that causes differentiation of proplastids to starch-containing amyloplasts and activation of genes involved in the starch biosynthesis pathway. Suppression of MADS29 expression by RNAi severely affected seed set. The surviving seeds were smaller in size, with developmental abnormalities in the embryo and reduced size of endosperm cells, which also contained loosely packed starch granules. Microarray analysis of overexpression and knockdown lines exhibited altered expression of genes involved in plastid biogenesis, starch biosynthesis, cytokinin signalling and biosynthesis.Item Microscale thermophoresis as a powerful tool for screening glycosyltransferases involved in cell wall biosynthesis(Springer Nature, 2020) Sharma, RitaIdentification and characterization of key enzymes associated with cell wall biosynthesis and modification is fundamental to gain insights into cell wall dynamics. However, it is a challenge that activity assays of glycosyltransferases are very low throughput and acceptor substrates are generally not available