The Effects of Low Temperature, Shading,Drought and Nitrogen on Cotton(Gossypium Hirsutum L.) Fiber Proteome and Their Relationship with Fiber Length Formation
|School||Nanjing Agricultural College|
|Keywords||Cotton (Gossypium hirsutum L.) Ecological stress Nitrogen rates Fiberelongation Fiber Length Proteome|
Fiber length is an important criterion of cotton quality and is determined by the polar elongation stage. Fiber length was affected by genotype, environmental condition and cultivation measures. Theis study was about the effects of ecological stress and nitrogrn rates on cotton fiber proteome and their relationship with the fiber length formation. In this paper, we use comparative proteomics approach to find the key proteins that are sensitive to ecological stress/nitrogen rates and combining with their function and dynamic change between the control and treatments to uncover the molecular mechanism response to ecological stress and nitrogen rates. The main results were as follows:1. The effects of low-temperature on the cotton fiber proteome and their relationship with the fiber length formationTwo cotton cultivars with different low temperature sensitivity were selected to study the effects of low temperature on cotton fiber proteome and their relationship with fiber length formation. And the results were as follows:low temperature shortened the cotton fiber length, and37proeins have significant change. The results showed that:the increased expression of phosphoenolpyruvate carboxylase, R1proteins and transketolase resulted in the relatively more production of malate and soluble sugar content, resulting in the relatively more generation of cell turgor; The expression of endo-xyloglucan transferase and expansin increased to ensure that the loose of in/exro-cellulose to intensifiy the fiber cell wall laxity; the expression of sucrose synthase and β-galactosidase enzyme was significantly increased, in favor of cellulose, synthetic galactose; the expression of actin and tubulin was observed decreased resulting in disruption of material transport and inhibited fiber arrangement; the change magnitude of the above low-temperature-responsive proteins in Kemian1was smaller than that in Sumian15, which may be the underlying reasons lead to differences among varieties with low temperature sensitivity. In addition, the change content of phosphoenolpyruvate carboxylase and the proton pyrophosphorylase and the activation of ethylene signaling pathway can be an indicator of cotton varieties resistant to low-temperature approach.2. The effects of shading on the cotton fiber proteome and their relationship with the fiber length formationThe investigation was aiming to understand the changes of the cotton fiber proteome and their relationships with cotton fiber length formation. The results showed that the fiber becomed shorter under shading condition. And there were40proteins changed significantly under low temperature. Combing with the expression characteristic of the above proteins under shading stress, we conclude that:CBL3and phospholipase D increasing at10DAA illustrated that the signal transduction was active during the early fiber elongation. It was useful for cotton fiber to regulate the base metabolism to adapt the shading stress. The decreases of the phosphofructokinase and dihydrolipoamide dehydrogenase resulted in the reduction of material synthesis and energy production. The decreasse of adenylyl cyclase associated protein, profiling and annexin caused the disorders of cytoskeletal structure. The increases of the SOD and APX could enhance the redoxiation activity of cotton fiber. Overall, the reduced metabolism of carbon/energy and the the disorders of cytoskeletal structure are the main reason for the short fibers under shading.3. The effects of short-term soil drought and rehydration on the cotton fiber proteome and their relationship with the fiber length formationFor the materials with NuCOTN33B, the normal irrigation experiment and short-term soil drough experiment during the flowering and boll-setting period were set to study the influences of short-term soil drought and rehydration on cotton fiber proteome and the relationship with cotton fiber length. The results showed that the fiber of cotton becomes shorter while the cotton relative water content decreased with drough experiment. After rehydration, though the cotton wilting was improved, the cotton fiber was still shorter than the control. In drought condition, there were163differentially expressed proteins which were closely related with drought stress. Mass spectrometry analysis led to the identification of132differentially expressed proteins:(1) the expression of sucrose synthase, bate glycosidase enzymes and UDP-L-rhamnose synthase and glycosyl transferase participated in the protein nucleoside sugar metabolism increased, especially at5DAA raised the largest amount.(2) The related enzymes which participated in methylation cycle, such as5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase, S-adenosylmethionine synthetase and adenosine kinase, showed ascendant trend. Active methylation cycle can provide methionine for ethylene synthesis, and for the other hand, methylation cycle could suberize the lignin to resist drought.(3)The proteins which participated in flavonoids synthesis, such as anthocyanidin, chalcone synthase and chalcone flavanone isomerase, raised expression, may be the result from the decreased fiber cells.(4) The ABA signal transduction pathway and14-3-3protein transduction pathway, raised expression in5DAA, may play an important role in drought tolerance of cotton fiber. In conclusion, the active nucleoside sugar metabolism was good for the synthesis of primary cell wall materials beneficial for the fiber elongation; methylation cycle had important significance in the process of fiber drought tolerance; the signal transduction system, especially hormone metabolism balance was effective for fiber cell to resist drought stress.4. The effects of nitrogen on the cotton proteome and their relationship with the fiber length formationThis experiment was carried out to study the effects of nitrogen rates on the cotton fiber proteome and their relationship with cotton fiber length formation. The results showed that: comparing to240kg·N·hm-2, the fiber length becomes shorter under0、480kg N hm-2. And there were87differentially expressed proteins that responsible for the nitrogen tolerance of cotton fiber. Mass spectrometry analysis led to the identification of61differentially expressed proteins. Combined with the expression characteristic of the61proteins, the conclusions were concluded as follows:The expression of triosephosphate isomerase and ATP synthase that participated in glysythse decreased resulted in the reduction of material synthesis and energy; The decreased expression of glutamine synthase and ALATra caused the reduction of nitrogen metabolism; the expression of sucrose synthase, UDP-D-glucose pyrophosphorylase and UDP-L-rhamnose synthase decreased which caused the reduction of the cellulose and UDP-L-rhamnose; the decreases of NAC3, PDI and proteasome blocked the targeting, transformation and degradation of proteins; the increases of chaperon and antioxidant could prevent the protein denaturation and elimination of ROS. The proteins involoved in the glycolysis and nitrogen metabolism, which increased to produce more material and energy production that useful for C/N metabolism. In conclusion, the reduction of C/N metabolism, the synthesis of cell wall components and the blockage of the proteins targeting, transformation and degradation were the reasons for reduction of fiber length under Okg N hm"2nitrogen rates; however, the reduction of the synthesis of cell wall components resulted in shorter fiber under480kg N hm-2nitrogen rate.