title: Down-regulation of a wheat alkaline/neutral invertase correlates with reduced host susceptibility to wheat stripe rust caused by Puccinia striiformis.
abstract: Numerous studies have found that sucrose (Suc) metabolism plays a crucial role in the environmental stress response of many plant species. The majority of Suc metabolism-associated reports refer to acid invertases (Ac-Invs). However, alkaline/neutral Invs (A/N-Invs) have been poorly studied. In this study, a wheat A/N-Inv gene, Ta-A/N-Inv1, with three copies located on chromosomes 4A, 4B, and 4D, was cloned from a wheat-Puccinia striiformis f. sp. tritici (Pst) interaction cDNA library. Transcripts of the three Ta-A/N-Inv1 copies were up-regulated in wheat leaves that were infected by Pst or had experienced certain abiotic treatments. Furthermore, the expression of Ta-A/N-Inv1 was decreased by treatment with exogenous hormones. Heterologous mutant complementation and subcellular localization revealed that Ta-A/N-Inv1 is a cytoplasmic invertase. Knocking down all three copies of Ta-A/N-Inv1 using the barley stripe mosaic virus-induced gene silencing system reduced the susceptibility of wheat to the Pst virulent pathotype CYR31, which is associated with pathogen-induced H2O2 accumulation and enhanced necrosis. Interestingly, 48h dark treatment of the Ta-A/N-Inv1-knockdown plants immediately after inoculation abrogated their enhanced resistance, suggesting that H2O2 production and its associated cell death and resistance in the Ta-A/N-Inv1-silenced plants require light. Consistent with this observation, photosynthesis and reactive oxygen species (ROS)-related genes were significantly up-regulated in the Ta-A/N-Inv1-knockdown plants infected by CYR31 under light exposure. These results suggest that Ta-A/N-Inv1 might act as a negative regulator in wheat disease resistance to Pst by increasing cytoplasmic hexose accumulation and downregulating photosynthesis of the leaves to avoid cell death due to excessive ROS production.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China China-Australia Joint Research Centre for Abiotic and Biotic Stress Management, Northwest A&F University, Yangling, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Han
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China.
authors.forename: Baoyu
authors.initials: B
authors.lastname: Huai
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China.
authors.forename: Peijing
authors.initials: P
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China China-Australia Joint Research Centre for Abiotic and Biotic Stress Management, Northwest A&F University, Yangling, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China China-Australia Joint Research Centre for Abiotic and Biotic Stress Management, Northwest A&F University, Yangling, China kangzs@nwsuaf.edu.cn.
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Kang
mesh_terms: D001487:Basidiomycota / Q000502:physiology; D016923:Cell Death; D003001:Cloning, Molecular; D015536:Down-Regulation; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D012441:Saccharomyces cerevisiae; D014908:Triticum / Q000201:enzymology* / Q000235:genetics / Q000382:microbiology*; D043324:beta-Fructofuranosidase / Q000378:metabolism*
chemical_list: D006861:Hydrogen Peroxide; D043324:beta-Fructofuranosidase
keywords: Alkaline/neutral invertase; Puccinia striiformis f. sp. tritici; photosynthesis; reactive oxygen species; susceptibility; wheat.