Publications of NIPGR Scientists

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Author: search.filters.author.Sharma, Nilesh KumarSubject: search.filters.subject.root

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    Lignin deposition in chickpea root xylem under drought
    (Taylor & Francis Group, 2020) Sharma, Nilesh Kumar; Gupta, Santosh Kumar
    In our recent publication, we have shown that a member of the Laccase family, LACCASE2 (LAC2) acted as a negative regulator of lignin deposition in the root xylem tissue of Arabidopsis thaliana. LAC2 messenger RNA (mRNA) level was post-transcriptionally regulated by microRNA 397b, which showed increased expression under water and phosphate deficiency, resulting in the downregulation of LAC2 expression In this report, we have investigated root growth and lignin deposition in an economically important legume crop chickpea (Cicer arietinum L.) in response to natural drought in soil-grown condition. In contrast to the growth retardation of Arabidopsis root in mannitol-supplemented medium, chickpea root showed an increase in length in low soil moisture condition. Lignin estimation in the primary root showed an increase in lignin content, which was substantiated by staining of root xylem. Drought treatment enhanced the expression of four out of six LAC genes tested, while the expression of two was downregulated. Our preliminary study indicateed a molecular mechanism of lignin deposition in chickpea root xylem during drought.
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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.