AtDREB2A-CA Influences Root Architecture and Increases Drought Tolerance in Transgenic Cotton
作者机构：Embrapa Recursos Genéticos e BiotecnologiaBrasíliaBrazil Empresa de Pesquisa Agropecuária de Minas GeraisUberabaBrazil Universidade Federal do Rio Grande do SulPorto AlegreBrazil Embrapa Clima TemperadoPelotasBrazil Universidade de BrasíliaBrasíliaBrazil Embrapa AgroenergiaBrasíliaBrazil Japan International Research Center for Agricultural Sciences(JIRCAS)TsukubaJapan Universidade Catolica de BrasiliaBrasiliaBrazil
出 版 物：《Agricultural Sciences》 (农业科学（英文）)
年 卷 期：2017年第8卷第10期
页 面：1195-1225页
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
基 金：supported by grants of funds from the Brazilian government(EMBRAPA CNPq CAPES and FAPDF)
主 题：Dehydration Responsive Element Binding Factors Water Deficit Tolerance Gossypium hirsutum Physiological Phenotyping Transcription Factor Stress-Inducible Promoter
摘 要：Drought is a major environmental factor limiting cotton (Gossypium hirsutum L.) productivity worldwide and projected climate changes could increase their negative effects in the future. Thus, targeting the molecular mechanisms correlated with drought tolerance without reducing productivity is a challenge for plant breeding. In this way, we evaluated the effects of water deficit progress on AtDREB2A-CA transgenic cotton plant responses, driven by the stress-inducible rd29 promoter. Besides shoot and root morphometric traits, gas exchange and osmotic adjustment analyses were also included. Here, we present how altered root traits shown by transgenic plants impacted on physiological acclimation responses when submitted to severe water stress. The integration of AtDREB2A-CA into the cotton genome increased total root volume, surface area and total root length, without negatively affecting shoot morphometric growth parameters and nor phenotypic evaluated traits. Additionally, when compared to wild-type plants, transgenic plants (17-T0 plants and its progeny) highlighted a gradual pattern of phenotypic plasticity tosome photosynthetic parameters such as photosynthetic rate and stomatal conductance with water deficit progress. Transgene also promoted greater shoot development and root robustness (greater and deeper root mass) allowing roots to grow into deeper soil layers. The same morpho-physiological trend was observed in the subsequent generation (17.6-T2). Our results suggest that the altered root traits shown by transgenic plants are the major contributors to higher tolerance response, allowing the AtDRE2A-CA-cotton plants to maintain elevated stomatal conductance and assimilate rates and, consequently, reducing their metabolic costs involved in the antioxidant responses activation. These results also suggest that these morpho-physiological changes increased the number of reproductive structures retained per plant (26% higher) when compared with its non-transgenic cou
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