title: Medicago truncatula genotypes Jemalong A17 and R108 show contrasting variations under drought stress.
abstract: Drought is one of the most significant abiotic stresses that restrict crop productivity. Medicago truncatula is a model legume species with a wide genetic diversity. We compared the differential physiological and molecular changes of two genotypes of M. truncatula (Jemalong A17 and R108) in response to progressive drought stress and rewatering. The MtNCED and MtZEP activation and higher abscisic acid (ABA) content was observed in Jemalong A17 plants under normal conditions. Additionally, a greater increase in ABA content and expression of MtNCED and MtZEP in Jemalong A17 plants than that of R108 plants were observed under drought conditions. A more ABA-sensitive stomatal closure and a slower water loss was found in excised leaves of Jemalong A17 plants. Meanwhile, Jemalong A17 plants alleviated leaf wilting and maintained higher relative water content under drought conditions. Exposed to drought stress, Jemalong A17 plants exhibited milder oxidative damage which has less H2O2and MDA accumulation, lower electrolyte leakage and higher chlorophyll content and PSII activity. Furthermore, Jemalong A17 plants enhanced expression of stress-upregulated genes under drought conditions. These results suggest that genotypes Jemalong A17 and R108 differed in their response and adaptation to drought stress. Given the relationship between ABA and these physiological responses, the MtNCED and MtZEP activation under normal conditions may play an important role in regulation of greater tolerance of Jemalong A17 plants to drought stress. The activation of MtNCED and MtZEP may lead to the increase of ABA content which may activate expression of drought-stress-regulated genes and cause a series of physiological resistant responses.
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Shi-Shuai
authors.initials: SS
authors.lastname: Luo
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Yan-Ni
authors.initials: YN
authors.lastname: Sun
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Zhou
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Li-Sha
authors.initials: LS
authors.lastname: Zhu
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Arfan
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China; Life Science and Technology College and Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang 621000, China.
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Zou
authors.affiliation: Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, State Key Laboratory of Hydraulics and Mountain River Engineering, Chengdu 610064, China. Electronic address: hhlin@scu.edu.cn.
authors.forename: Hong-Hui
authors.initials: HH
authors.lastname: Lin
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000064:Acclimatization / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005838:Genotype; D046913:Medicago truncatula / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D013312:Stress, Physiological / Q000235:genetics; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D002734:Chlorophyll; D000040:Abscisic Acid
keywords: Abscisic acid; Drought; Medicago truncatula; Oxidative damage; Stomatal aperture; Stress-up-regulated genes