Studies On The Stress Resistance Functions Of OsSCP Gene

The serinc carboxypoptidascs belong to a large family. Studies have found that serine earboxypeptidases are involved in many important biochemical reactions, including protein folding, herbicide conjugation, secondary metabolite biosynthesis and so on. Serine caboxypeptidases play an important role in cellular regulation of plant, synthesis of plant secondary metabolites and the regulatory role in stress tolerance. OsSCP over-expression vector was constructed and transformed into rice. The OsSCP over-expression and mutant plants were used as experimental materials for the aboitic stress related functional analysis in rice. The main results were as the following:1. Plant over-expression vector for OsSCP was constructed successfully. Transgenic rice plants were obtained by Agrobacleriume-mediaicd transformation.2. OsSCP overexpression transgenic rice improved drought tolerance and high temperature resistance compared to control, while mutant of OsSCP showed weaker resistance to drought and high temperature stresses. No significant differences among expression of OsSCP. mutant of OsSCP and WT were found under salt stress.3. Investigation of drought treatment at different stages of OsSCP transgenic seedlings revealed that OsSCP gene has no effect on rice drought tolerance at the seed germination stage. But OsSCP overexpression showed strong drought resistance at the seedling, tillering and booting stages, while drought resistance of OsSCP mutants is poor.4. OsSCP overexpression transgenic rice and wild type plants at tillering stage and booting stage were subjected to drought stress by stopping watering. Physiological and biochemical analysis such as proline content. MDA content and chlorophyll leaching indicated thai OsSCP overexpression displayed stronger tolerance than wild type plants. However. OsSCP mutant transgenic plants were sensitive to drought compared to wild type.5. SOD, POD and CAT activities in OsSCP overexpression plants were higher than wild-type, while mutant were lower. POD activity in OsSCP overexpression was increased to very significant level after drought treatment.6. After ABA treatment, OsSCP overexpression transgenic seedlings reduced ABA sensitivity compared to wild type and OsSCP mutant.