HvEXPB7, a novel β-expansin gene revealed by the root hair transcriptome of Tibetan wild barley, improves root hair growth under drought stress

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DOI

  • Xiaoyan He, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China
  • Jianbin Zeng, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China
  • Fangbin Cao, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China
  • Imrul Mosaddek Ahmed, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China
  • Guoping Zhang, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China
  • Eva Vincze
  • Feibo Wu, Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, China

Tibetan wild barley is a treasure trove of useful genes for crop improvement including abiotic stress tolerance, like drought. Root hair of single-celled structures plays an important role in water and nutrition uptake. Polyethylene-glycol-induced drought stress hydroponic/petri-dish experiments were performed, where root hair morphology and transcriptional characteristics of two contrasting Tibetan wild barley genotypes (drought-tolerant XZ5 and drought-sensitive XZ54) and drought-tolerant cv. Tadmor were compared. Drought-induced root hair growth was only observed in XZ5. Thirty-six drought tolerance-associated genes were identified in XZ5, including 16 genes specifically highly expressed in XZ5 but not Tadmor under drought. The full length cDNA of a novel β-expansin gene (HvEXPB7), being the unique root hair development related gene in the identified genes, was cloned. The sequence comparison indicated that HvEXPB7 carried both DPBB_1 and Pollon_allerg_1 domains. HvEXPB7 is predominantly expressed in roots. Subcellular localization verified that HvEXPB7 is located in the plasma membrane. Barley stripe mosaic virus induced gene silencing (BSMV-VIGS) of HvEXPB7 led to severely suppressed root hairs both under control and drought conditions, and significantly reduced K uptake. These findings highlight and confer the significance of HvEXPB7 in root hair growth under drought stress in XZ5, and provide a novel insight into the genetic basis for drought tolerance in Tibetan wild barley.

Original languageEnglish
JournalJournal of Experimental Botany
Volume66
Issue22
Pages (from-to)7405-7419
Number of pages15
ISSN0022-0957
DOIs
Publication statusPublished - 28 Sep 2015

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