title: Analysis of different strategies adapted by two cassava cultivars in response to drought stress: ensuring survival or continuing growth.
abstract: Cassava is one of the most drought-tolerant crops, however, the underlying mechanism for its ability to survive and produce under drought remains obscure. In this study, two cassava cultivars, SC124 and Arg7, were treated by gradually reducing the soil water content. Their responses to the drought stress were examined through their morphological and physiological traits and isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analysis. SC124 plants adapted a 'survival' mode under mild drought stress as evidenced by early stomatal closure and a reduction in the levels of various photosynthetic proteins and photosynthetic capacity, resulting in early growth quiescence. In contrast, Arg7 plants underwent senescence of older leaves but continued to grow, although at a reduced rate, under mild drought. SC124 plants were more capable of surviving prolonged severe drought than Arg7. The iTRAQ analysis identified over 5000 cassava proteins. Among the drought-responsive proteins identified in the study were an aquaporin, myo-inositol 1-phosphate synthases, and a number of proteins involved in the antioxidant systems and secondary metabolism. Many proteins that might play a role in signalling or gene regulation were also identified as drought-responsive proteins, which included several protein kinases, two 14-3-3 proteins, several RNA-binding proteins and transcription factors, and two histone deacetylases. Our study also supports the notion that linamarin might play a role in nitrogen reallocation in cassava under drought.
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, PR China College of Agronomy, Hainan University, Haikou, PR China.
authors.forename: Pingjuan
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong, PR China.
authors.forename: Pei
authors.initials: P
authors.lastname: Liu
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong, PR China.
authors.forename: Jiaofang
authors.initials: J
authors.lastname: Shao
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, PR China Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Haikou, PR China.
authors.forename: Chunqiang
authors.initials: C
authors.lastname: Li
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Yan
authors.affiliation: Department of Biology, Hong Kong Baptist University, Hong Kong, PR China Partner State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Hong Kong, PR China mmpeng_2000@yahoo.com yxia@hkbu.edu.hk.
authors.forename: Yiji
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, PR China Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Haikou, PR China mmpeng_2000@yahoo.com yxia@hkbu.edu.hk.
authors.forename: Ming
authors.initials: M
authors.lastname: Peng
mesh_terms: D055864:Droughts; D018506:Gene Expression Regulation, Plant; D002365:Manihot / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014867:Water
keywords: Cassava; cyanogenic glycosides; drought tolerance; drought-responsive protein; proteomics; stress response.