Institutional Publications

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Author: search.filters.author.Sharma, Nilesh KumarSubject: search.filters.subject.Cicer arietinum L

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    MicroRNA397 regulates tolerance to drought and fungal infection by regulating lignin deposition in chickpea root
    (John Wiley & Sons, 2023) Sharma, Nilesh Kumar; Yadav, Shalini; Gupta, Santosh Kumar; Irulappan, Vadivelmurugan; Francis, Aleena; Senthil-Kumar, Muthappa; Chattopadhyay, Debasis
    Plants deposit lignin in the secondary cell wall as a common response to drought and pathogen attacks. Cell wall localised multicopper oxidase family enzymes LACCASES (LACs) catalyse the formation of monolignol radicals and facilitate lignin formation. We show an upregulation of the expression of several LAC genes and a downregulation of microRNA397 (CamiR397) in response to natural drought in chickpea roots. CamiR397 was found to target LAC4 and LAC17L out of twenty annotated LACs in chickpea. CamiR397 and its target genes are expressed in the root. Overexpression of CamiR397 reduced expression of LAC4 and LAC17L and lignin deposition in chickpea root xylem causing reduction in xylem wall thickness. Downregulation of CamiR397 activity by expressing a short tandem target mimic (STTM397) construct increased root lignin deposition in chickpea. CamiR397-overexpressing and STTM397 chickpea lines showed sensitivity and tolerance, respectively, towards natural drought. Infection with a fungal pathogen Macrophomina phaseolina, responsible for dry root rot (DRR) disease in chickpea, induced local lignin deposition and LAC gene expression. CamiR397-overexpressing and STTM397 chickpea lines showed more sensitivity and tolerance, respectively, to DRR. Our results demonstrated the regulatory role of CamiR397 in root lignification during drought and DRR in an agriculturally important crop chickpea.
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    Root-specific expression of chickpea cytokinin oxidase/dehydrogenase 6 leads to enhanced root growth, drought tolerance and yield without compromising nodulation
    (John Wiley & Sons, 2020) Khandal, Hitaishi; Gupta, Santosh Kumar; Dwivedi, Vikas; Mandal, Drishti; Sharma, Nilesh Kumar; Vishwakarma, Niraj Kumar; Pal, Lalita; Choudhary, Megha; Francis, Aleena; Malakar, Paheli; Singh, Nagendra Pratap; Sharma, Kapil; Sinharoy, Senjuti; Singh, Narendra Pratap; Sharma, Rameshwar; Chattopadhyay, Debasis
    Cytokinin group of phytohormones regulate root elongation and branching during post‐embryonic development. Cytokinin degrading enzymes cytokinin oxidases/dehydrogenases (CKXs) have been deployed to investigate biological activities of cytokinin and to engineer root growth. We expressed chickpea cytokinin oxidase 6 (CaCKX6) under the control of a chickpea root‐specific promoter of CaWRKY31 in Arabidopsis thaliana and chickpea having determinate and indeterminate growth patterns, respectively, to study the effect of cytokinin depletion on root growth and drought tolerance. Root‐specific expression of CaCKX6 led to a significant increase in lateral root number and root biomass in Arabidopsis and chickpea without any penalty to vegetative and reproductive growth of shoot. Transgenic chickpea lines showed increased CKX activity in root. Soil‐grown advanced chickpea transgenic lines exhibited higher root‐to‐shoot biomass ratio and enhanced long‐term drought tolerance. These chickpea lines were not compromised in root nodulation and nitrogen fixation. The seed yield in some lines was up to 25% higher with no penalty in protein content. Transgenic chickpea seeds possessed higher levels of zinc, iron, potassium and copper. Our results demonstrated the potential of cytokinin level manipulation in increasing lateral root number and root biomass for agronomic trait improvement in an edible legume crop with indeterminate growth habit.