Publications of NIPGR Scientists

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Subject: search.filters.subject.Gymnosperms

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    Giberellic acid-stimulated transcript proteins evolved through successive conjugation of novel motifs and their subfunctionalization
    (American Society of Plant Biologists, 2019) Kumar, Ashutosh; Singh, Alka; Kumar, Pramod; Sarkar, Ananda K.
    Gibberellic Acid Stimulated Transcript (GAST)-like genes encode small polypeptides, some of which have been implicated in diverse biological processes regulating plant growth and development. However, the occurrence of GASTs among plants, their protein structures, and the mechanisms by which they evolved remain elusive. Here, using a customized workflow, we report genes encoding GAST proteins, identify novel motifs and evolutionary patterns contributing to sub-functionalization of GAST domains, and explore functional conservation across diverse plants. We show that GAST-like sequences evolved initially in the vascular plant Selaginella moellendorffii, after the divergence from bryophytes, and later emerged in gymnosperms and angiosperms. GASTs in angiosperms are characterized by four conserved novel motifs; however, relatively fewer conserved motifs exist in pteridophytes and gymnosperms. Phylogenetic analysis revealed that the GCR1 motif evolved early in S. moellendorffii GAST, which further acquired sub-functionalization through successive conjugation of other motifs and remained conserved across plants, as supported by their collinearity. Functional characterization of two orthologues from the dicot Arabidopsis thaliana (Ath-GASA10) and the monocot rice (Oryza sativa; Osa-GAST9) suggests hormonal regulation, novel roles in seed germination, and functional conservation among diverse plant groups. Computational modelling predicts that these GAST genes are regulated by several factors, including the phytohormones GA and ABA, through conserved cis-motifs present in their promoters, and that they might act as signaling molecules in a complex feedback loop. Thus, our study identifies GASTs and their encoded proteins, uncovers their structure, novel motifs, and evolutionary pattern among plants, and suggests their functional conservation.
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    Neomycin: an effective inhibitor of jasmonate-induced reactions in plants
    (Springer Nature, 2019) Vadassery, Jyothilakshmi; Ballhorn, Daniel J.; Fleming, Steven R.; Mazars, Christian; Pandey, Shree P.; Schmidt, Axel; Schuman, Meredith C.; Yeh, Kai‑Wun; Yilamujiang, Ayufu; Mithöfer, Axel
    Jasmonates are important phytohormones involved in both plant developmental processes as well as defense reactions. Many JA-mediated plant defense responses have been studied in model plants using mutants of the jasmonate signaling pathway. However, in plant species where JA-signaling mutants are not accessible, the availability of a tool targeting JA signaling is crucial to investigate jasmonate-dependent processes. Neomycin is a poly-cationic aminoglycoside antibiotic that blocks the release of Ca2+ from internal stores. We examined the inhibitory activities of neomycin on different jasmonate-inducible responses in eight different plant species: Intracellular calcium measurements in Nicotiana tabacum cell culture, Sporamin gene induction in Ipomoea batatas, PDF2.2 gene expression in Triticum aestivum, Nepenthesin protease activity measurement in Nepenthes alata, extrafloral nectar production in Phaseolus lunatus, nectary formation in Populus trichocarpa, terpene accumulation in Picea abies, and secondary metabolite generation in Nicotiana attenuata. We are able to show that neomycin, an easily manageable and commercially available compound, inhibits JA-mediated responses across the plant kingdom.