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A secreted chitinase‐like protein (OsCLP) supports root growth through calcium signaling in Oryza sativa

Wu, Jingni, Wang, Yiming, Kim, Sang Gon, Jung, Ki‐Hong, Gupta, Ravi, Kim, Joonyup, Park, Younghoon, Kang, Kyu Young, Kim, Sun Tae
Physiologia plantarum 2017 v.161 no.2 pp. 273-284
Oryza sativa, atomic absorption spectrometry, calcium, calcium signaling, calreticulin, carbohydrate structure, chaperonins, chitinase, glycolysis, growth retardation, mutants, phosphoglycerate kinase, proteomics, rice, root growth, roots, shoots, staining, transfer DNA
Chitinases belong to a conserved protein family and play multiple roles in defense, development and growth regulation in plants. Here, we identified a secreted chitinase‐like protein, OsCLP, which functions in rice growth. A T‐DNA insertion mutant of OsCLP (osclp) showed significant retardation of root and shoot growth. A comparative proteomic analysis was carried out using root tissue of wild‐type and the osclp mutant to understand the OsCLP‐mediated rice growth retardation. Results obtained revealed that proteins related to glycolysis (phosphoglycerate kinase), stress adaption (chaperonin) and calcium signaling (calreticulin and CDPK1) were differentially regulated in osclp roots. Fura‐2 molecular probe staining, which is an intracellular calcium indicator, and inductively coupled plasma‐mass spectrometry (ICP‐MS) analysis suggested that the intracellular calcium content was significantly lower in roots of osclp as compared with the wild‐type. Exogenous application of Ca²⁺ resulted in successful recovery of both primary and lateral root growth in osclp. Moreover, overexpression of OsCLP resulted in improved growth with modified seed shape and starch structure; however, the overall yield remained unaffected. Taken together, our results highlight the involvement of OsCLP in rice growth by regulating the intracellular calcium concentrations.