Browsing by Author "Upadhyay, Priya"

Now showing 1 - 2 of 2

Microscopic and transcriptomic analyses of Dalbergoid legume peanut reveal a divergent evolution leading to Nod Factor dependent epidermal crack-entry and terminal bacteroid differentiation
(American Phytopathological Society, 2022) Raul, Bikash; Bhattacharjee, Oindrila; Ghosh, Amit; Upadhyay, Priya; Tembhare, Kunal; Singh, Ajeet; Shaheen, Tarannum; Ghosh, Asim Kumar; Torres-Jerez, Ivone; Krom, Nick; Clevenger, Josh; Udvardi, Michael; Scheffler, Brian E.; Ozias-Akins, Peggy; Sharma, Ravi Datta; Bandyopadhyay, Kaustav; Gaur, Vineet; Kumar, Shailesh; Sinharoy, Senjuti
Root nodule symbiosis (RNS) is the pillar behind sustainable agriculture and plays a pivotal role in the environmental nitrogen cycle. Most of the genetic, molecular, and cell-biological knowledge on RNS come from model legumes that exhibit a root-hair mode of bacterial infection in contrast to the Dalbergoid legumes exhibiting crack-entry of rhizobia. As a step towards understanding this important group of legumes, we have combined microscopic analysis and temporal transcriptome to obtain a dynamic view of plant gene expression during Arachis hypogaea (peanut) nodule development. We generated a comprehensive transcriptome data by mapping the reads to A. hypogaea, and two diploid progenitor genomes. Additionally, we performed BLAST searches to identify nodule-induced yet-to-be annotated peanut genes. Comparison between peanut, Medicago truncatula, Lotus japonicus, and Glycine max showed upregulation of 61 peanut orthologs among 111 tested known RNS-related genes, indicating conservation in mechanisms of nodule development among members of the Papilionoid family. Unlike model legumes, recruitment of class 1 phytoglobin derived symbiotic hemoglobin (SymH) in peanut indicates diversification of oxygen scavenging mechanisms in the Papilionoid family. Finally, absence of cysteine-rich motif-1 containing-NCRs, but the recruitment of defensin like NCRs suggest a diverse molecular mechanism of terminal bacteroid differentiation. In summary, our work describes genetic conservation and diversification in legume-rhizobial symbiosis in the Papilionoid family, as well as among members of the Dalbergoid legumes.
Organized peripheral vascular strand development in nodules is controlled by a bHLH/HLH heterodimer
(John Wiley & Sons, 2026) Srivastava, Deevita; Bhadu, Vikash; Sahoo, Rudra Narayan; Ghosh, Asim Kumar; Upadhyay, Priya; Bhardwaj, Akanksha; Udvardi, Michael K; Ranjan, Aashish; Sinharoy, Senjuti
The Leguminosae family can develop root nodules with symmetrical peripheral vascular-strands (PVSs). Medicago truncatula forms indeterminate nodules with PVSs. The PVSs elongate directly from the root toward the nodule apex, maintaining a symmetrical organization and facilitating the formation of the cylindrical nodule structure. By combining genetic, biochemical, and genomic tools, we have shown that two basic Helix-Loop-Helix groups of transcription factors, MtbHLH1 (renamed Nodule Vascular bundle Development 1 (NVD1)) and NVD2, control the development of symmetrical PVSs in M. truncatula. In nvd1 nodules, PVSs drift toward the infection zone, generating aberrantly shaped nodules. NVD1 activates its expression along with NVD2, a transcriptional regulator. NVD1 functions downstream of auxin signaling. Transcriptome sequencing of nvd1 and nvd2 nodules, combined with visualization of auxin and cytokinin (CK) signal outputs, revealed disrupted auxin and CK signaling in nvd nodules. Furthermore, ectopic expression of the auxin biosynthetic enzyme (MtYUCCA8) under pMtNVD1 and pMtNVD2 resulted in defective PVSs. Mutant nvd2 nodules display asymmetric PVSs. NVD2 regulates the transcriptional activity of NVD1 by forming heterodimers with it. The formation of symmetrical PVSs depends on the balanced presence of NVD1 and NVD2. Our findings highlight the pivotal role of the NVD1-NVD2 interaction in shaping the development of symmetrical PVSs.