| Stressful environmental stimuli, such as salinity, drought, and cold can cause an enormous impact on plant growth and development. These adversely environmental conditions also have seriously hampered the production of crops. To adapt such detrimental conditions, plants have developed a broad range of defense strategies and sophisticated signal perception and transduction networks to cope with their environment stresses, requiring many genes regulated by abiotic stresses. To date, a broad set of genes regulated by salt and drought stress have been identified and overexpression of them enhanced tolerance to abiotic stress. However, the biological functions of many genes related to abiotic stress are still largely unknown in higher plants and remained to be identified. In this paper, we reported the results of the biological functions of GmPKl2, GmCBL1and AtBSK5by using different molecular genetic approaches in detail.1、 A number of studies have demonstrated that the calcineurin B-like (CBL) genes are involved in modulating various abiotic stresses responses. In this study, a CBL gene was isolated from soybean. To our best knowledge, there is no report about CBL proteins from soybean until now. Our results showed that GmCBL1was induced by various abiotic stresses and phytohormones. Amino acids analysis showed that there was a putative N-myrislation motif in CBL1, and subcellular localization result revealed CBL1was present at plasma membrane. Overexpression of GmCBL1promoted salt and drought tolerance in Arabidopsis through regulating a series of stress responsive genes expression. In addition, GmCBL1overexpression promoted hypocotyl elongation in Arabidopsis in a light-dependent manner. Further research showed that GmCBLl might modulate gibberellin biosynthesis for hypocotyl development and act as a molecular link of cross-talk between gibberellin and light signaling.2、 In the present study, we isolated a stress-induced gene encoded putative protein kinase named GmPK12from soybean, which was also activated by various stimuli. Subcellular localization showed GmPK12was present at plasma membrane and nucleus. GUS expression driven by the promoter of GmPK12was observed mainly at vascular system in transgenic Arabidopsis. Overexpression of GmPK12obviously enhanced salt and cold tolerance in Arabidopsis and tobacco, as well as germination potential. Its overproduction also improved stress tolerance in wheat. Further analysis showed that a number of stress responsive genes were induced and cell membrane stability was improved through reducing membrane damage in transgenic plants.3、 In this study, we also isolated a abiotic stress-induced brassinosteroid signaling kinase (BSK) named AtBSK5. AtBSK5transcripts were detected in various tissues, and were induced by stimuli including salt and drought, as well as phytohormones of BR and abscisic acid (ABA). Loss-of-function mutant bsk5exhibited hypersensitivity to salinity and ABA. Further study showed that germination deficiency in bsk5under saline conditions may partially be due to ABA accumulation. Mutations of the BSK5gene altered the expression of several ABA biosynthetic and signaling pathway genes.In conclusion, gain-of-function and loss-of-function suggest that two putative protein kinases studied in this research, GmPK12and AtBSK5, function positively in salt and cold stresses responses and negatively in ABA signaling. The soybean GmCBL1was shown to play diverse roles in stress response and plant development, which provides further insight into the complex roles of CBLs in plants. There genes could be a potential candidate genes for crop improvement. |
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