The Mechanism Analyzed Of The Material Transport Of Rice Stem And Sheath In Response To Alternate Wetting And Moderate Soil Drying At Grain Filling Stage

Rice is one of the most important crops in the world.It has the vital significance to achieve rice high-yield that establish a reasonable way of water management.Stem and sheath is the main channel for organic compounds,water and nutrient transport during the rice source and library.It has an important significance for rice high-yield that adopt the reasonable cultivation measure to enhance the material transport ability of stem and sheath.This study used the stem and sheath of rice("Jin Hui 809 ")as the experimental material,and analyzed the changes in physiological and agronomic traits of rice stem and sheath under moderate drought stress(dry-wet alternate irrigation)during the grain filling stage.The results showed that the transport rate and conversion of stem and sheath increased by 9.87%and 8.37%respectively,and the seed setting rate of inferior grain,thousand kernel weight and yield increased by 14.30%,2.98%and 2.98%respectively.Namely,the moderate dry-wet alternate irrigation method could effectively promote the stem sheath material transport and conducive to the formation of rice high-yield.Furthermore,this study analyzed the material transport mechanism of the stem and sheath under the dry-wet alternate irrigation by two-dimensional electrophoresis technology.The protein expression profiles of stem and sheath 10,20 and 30 days after flowering were constructed.We found 220 differentially expressed proteins,and successfully identified 166 proteins,including 71 proteins in stem and 95 proteins in leaf sheath.Based on the bioinformatics analysis of protein function,we found that the degradation of photosynthesis-related proteins,such as 1,5-diphosphate ribulose carboxylase,chlorophyll a-b binding protein,photosynthetic system I,Transketolase and oxygen evolution,could promote the aging of stem and leaf sheath ahead of time,which were favolable to the transshipment of carbohydrates from the "source" to the"library".The up-regulated of stress related proteins(Heat shock protein,ATP dependent on zinc metal protease,peroxidase,salt stress protein,L-ascorbic acid salt peroxidase,extension factor EF1 and REDOX enzymes)effectively enhanced the material reserve and transport capacity of stem and leaf sheath.The up-regulated of energy metabolism-related proteins(triose phosphate isomerase,enolase,alcohol dehydrogenase,glyceric acid phosphate mutase,fructose,glyceraldehyde 3-phosphate dehydrogenase kinase,glyceric acid phosphate kinase,aspartate transaminase,yanhusuo acyl acetoacetic acid hydrolase,glutamine synthetase and ATP synthetase)enhanced the energy metabolism of stem and leaf sheaths,generated more energy for stem and sheath against drought stress and to promote material transfer.In addition,the present study also showed that the ABA/WMD induced proteins and 14-3-3 protein play an important role in the signal transduction in stem and sheath in response to the drought stress.In conclusion,our results suggest that the rice stem and sheath might response to moderate soil drying by efficiently.remobilize assimilates from stem and sheath.to grain through coordinated protein expression.This study has elucidated the molecular mechanism of promoting the material transport in stem and sheath by water management and regulation on proteomics level,and deepened the theory of high-yielding cultivation of rice.