An Jing, Hu Zhenmin, Che Benning, Chen Haiying, Yu Bingjun, Cai Weiming
Laboratory of Plant Stress Biology, College of Life Sciences, Nanjing Agricultural UniversityNanjing, China.
Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of SciencesShanghai, China.
Front Plant Sci. 2017 Jul 17;8:1232. doi: 10.3389/fpls.2017.01232. eCollection 2017.
The gene was previously demonstrated to have high water channel activity by its heterologous expression in oocytes and in yeast; it also plays a significant role in growth of transgenic plants under favorable conditions and has enhanced tolerance toward salt and drought treatment. In this work, we first investigated the physiological effects of heterologous expression in soybean cotyledon hairy roots or composite plants mediated by toward enhanced salt tolerance. The transgenic soybean plants mediated by the pollen tube pathway, represented by the lines N and J11, were analyzed at the physiological and molecular levels for enhanced salt tolerance. The results showed that in terms of root-specific heterologous expression, the -transformed soybean cotyledon hairy roots or composite plants displayed superior salt tolerance compared to the empty vector-transformed ones according to the mitigatory effects of hairy root growth reduction, drop in leaf RWC, and rise in REL under salt stress. Additionally, declines in K content, increases in Na content and Na/K ratios in the hairy roots, stems, or leaves were effectively alleviated by transformation, particularly the stems and leaves of composite soybean plants. At the whole plant level, -trasgenic soybean lines were found to possess stronger root vigor, reduced root and leaf cell membrane damage, increased SOD, POD, CAT, and APX activities, steadily increased leaf Tr, RWC, and Pn values, and smaller declines in chlorophyll and carotenoid content when exposed to salt stress compared to wild type. Moreover, the distribution patterns of Na, K, and Cl in the roots, stems, and leaves of salt-stressed transgenic plants were readjusted, in that the absorbed Na and Cl were mainly restricted to the roots to reduce their transport to the shoots, and the transport of root-absorbed K to the shoots was simultaneously promoted. transformation into soybean plants enhanced the expression of some stress-related genes (, , , and ) in the roots and leaves under salt treatment. This indicates that the causes of enhanced salt tolerance of heterologous transformed soybean are associated with the positive regulation on water relations, ion homeostasis, and ROS scavenging under salt stress both at root-specific and whole plant levels.
该基因先前已通过其在卵母细胞和酵母中的异源表达被证明具有高水通道活性；它在有利条件下对转基因植物的生长也起着重要作用，并且对盐和干旱处理具有增强的耐受性。在这项工作中，我们首先研究了由其介导的在大豆子叶毛状根或复合植物中的异源表达对增强耐盐性的生理影响。以N系和J11系为代表的通过花粉管途径介导的转基因大豆植株在生理和分子水平上进行了耐盐性增强分析。结果表明，就根特异性异源表达而言，根据盐胁迫下毛状根生长减少、叶片相对含水量下降和相对电导率上升的缓解效应，与空载体转化的大豆子叶毛状根或复合植物相比，-转化的大豆子叶毛状根或复合植物表现出更高的耐盐性。此外，转化有效地缓解了毛状根、茎或叶中钾含量的下降、钠含量和钠/钾比的增加，特别是复合大豆植株的茎和叶。在整株水平上，发现-转基因大豆品系与野生型相比，在盐胁迫下具有更强的根系活力、减少的根和叶细胞膜损伤、增加的超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性、稳定增加的叶片蒸腾速率（Tr）、相对含水量（RWC）和净光合速率（Pn）值，以及叶绿素和类胡萝卜素含量较小的下降。此外，盐胁迫转基因植物根、茎和叶中钠、钾和氯的分布模式得到了重新调整，即吸收的钠和氯主要限制在根部以减少其向地上部的运输，同时促进根部吸收的钾向地上部的运输。转化到大豆植株中增强了盐处理下根和叶中一些胁迫相关基因（、、、和）的表达。这表明异源转化大豆耐盐性增强的原因与在根特异性和整株水平上盐胁迫下对水分关系、离子稳态和活性氧清除的正向调节有关。
