Institutional Publications
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Item Monogalactosyl Diacylglycerol Synthase 3 affects phosphate utilization and acquisition in rice(Oxford University Press, 2022) Verma, Lokesh; Bhadouria, Jyoti; Rupam, Bhunia Kumar; Singh, Shweta; Panchal, Poonam; Bhatia, Chitra; Eastmond, Peter J; Giri, JitenderGalactolipids are essential for compensating for the loss of phospholipids by “membrane lipid remodeling” in plants under phosphorus (P) deficiency. Monogalactosyl diacylglycerol (MGDG) synthases catalyze the synthesis of MGDG which is further converted into digalactosyl diacylglycerol (DGDG), later replacing phospholipids in the extraplastidial membranes. However, the roles of these enzymes are not well explored in rice. In this study, the rice MGDG synthase gene, OsMGD3 was identified and functionally characterized. We showed that plant phosphate (Pi) status and transcription factor OsPHR2 are involved in the transcriptional regulation of OsMGD3. CRISPR/Cas9 knockout (KO) and overexpression (OE) lines of OsMGD3 were generated to explore its potential role in rice adaptation to Pi deficiency. Compared to WT, OsMGD3 KO lines displayed a reduction while OE lines showed an enhanced, Pi acquisition and utilization. Further, OsMGD3 showed a predominant role in roots, altering lateral root growth. Our comprehensive lipidomic analysis revealed the role of OsMGD3 in membrane lipid remodeling in addition to a role in regulating diacylglycerol and phosphatidic acid levels that affected the expression of Pi transporters. Our study highlights the role of OsMGD3 in affecting both internal P utilization and P acquisition in rice.Item OsJAZ9 overexpression modulates jasmonic acid biosynthesis and potassium deficiency responses in rice(Springer Nature Publishing AG, 2020) Singh, Ajit Pal; Pandey, Bipin K.; Mehra, Poonam; Heitz, Thierry; Giri, JitenderPotassium (K) represents up to 10% of the plant’s total dry biomass, and its deficiency makes plants highly susceptible to both abiotic and biotic stresses. K shortage results in the inhibition of root and shoots growth, but the underlying mechanism of this response is unclear. Our RNA-Seq and qPCR analysis suggested leading roles for JA pathway genes under K deficiency in rice. Notably, K deficiency and JA application produced similar phenotypic and transcriptional responses. Here, we integrated molecular, physiological and morphological studies to analyze the role of OsJAZ9 in JA homeostasis and K deficiency responses. We raised OsJAZ9 over-expression, knockdown, transcriptional reporter, translational reporter and C-terminal deleted translational reporter lines in rice to establish the role of JA signaling in K ion homeostasis. JA profiling revealed significantly increased JA-Ile levels in OsJAZ9 OE lines under K deficiency. Furthermore, we established that OsJAZ9 overexpression and knockdown result in K deficiency tolerance and sensitivity, respectively, by modulating various K transporters and root system architecture. Our data provide evidence on the crucial roles of OsJAZ9 for improving K deficiency tolerance in rice by altering JA levels and JA responses.
