Effects Of Mustard Aldehyde, Coniferyl Aldehyde On Growth And Development Of Cotton Fiber In Vitro And Expression Of Related Gene

Cotton is not only the most important economic crop in textiles, but also plays an important role in ournational economy and people’s life. China’s cotton crop which can basically meet the needs of productionranks first in the world. But our country cotton length is so single and weak that difficult to meet thepeople’ growing material and cultural needs. Research shows that Metabolism of phenylalanine and itsproducts exist in the development of cotton fiber. In cotton fiber metabolic pathways, Metabolism ofphenylalanine which is second only to cellulose metabolism may exert an important influence upon cottonfiber development and quality characters. Metabolism of phenylalanine starts in benzoic acid. Through aseries of hydroxylation, methylation, redox reaction, Metabolism of phenylalanine formats threemethylated monomer (fenugreek alcohol, coniferyl alcohol and ethyl alcohol) that be polymerized to H, G,S lignin. The use of transgenic technology can reduce the content of lignin and change lignin monomer (S,G) constitute which change the nature of plant cell wall through down-regulating or inhibiting theexpression of phenylpropanoid pathway genes. Phenylpropanoid compounds and the content of ligninmonomer type ratio (S: G) have effect in cell wall properties. Here I study the influence of two differentlignin intermediate metabolites (coniferyl aldehyde and mustard aldehyde) on the growth and developmentof cotton fiber.The study using the intermediates of phenylpropanoid metabolic：mustard aldehyde, coniferylaldehyde conducted the test of feeding fertilized ovules (0DPA) of fibers in vitro culture, respectively.First, combined with digital image processing technology, the growth state of cultivated fiber werecompared and analyzed under different periods (5d,10d,15d,20d); Subsequently, analyzed the relativeexpression level of phenylpropanoid metabolism pathway key enzyme gene and fiber elongation relatedgenes by RT-PCR technology，that in different developmental stages and with different feeding substrate;Finally, analyzed the cotton fiber by acetyl bromide method which are cultured after27d that fed ondifferent substrates. The main results run follows:（1）Feeding a certain concentration of mustard aldehyde,coniferyl aldehyde（100μmol/L、200μmol/L）on cotton can grow inhibition. The most degree of inhibition are mustard aldehyde200μmol/L, the lengthof the inhibitory rate is10.56%（P＜0.01）, area of inhibition rate is14.5%（P＜0.01）; followed by coniferylaldehyde200μmol/L treatment, length of inhibition rate is7.99%（P＜0.01）, area of inhibition rate is13.9%（P＜0.01）. Mustard aldehyde100μmol/L with CK length6.23%（P＜0.05）, area reduced8.59%（P＜0.05）; coniferyl aldehyde100μmol/L treatment with CK reduced by4.58%（P＜0.05）, area isreduced by7.23%（P＜0.05）.（2）In order to explore the phenylpropanoid compounds impact on cotton fiber development，we used theRT-PCR technology to study the relative expression of phenylpropanoid metabolic pathway key enzymesgenes and fiber elongation related genes on fibers, feeding with different substrate of variousdevelopmental stages.The research showed that the expression of experimental groupPAL,C4H,O-methylase gene and enzyme gene who participate in the reduction reaction was higher thanCK, and high concentrations (200μmol/L) treatment had higher expression amount than lowconcentration (100μmol/L) treatment.The result shows that the treatment of100μmol/L and200μmol/Lmustard aldehyde and aconiferyl aldehyde treatment can increase genes expression related to the phenylpropanoid metabolic pathway, the high concentrations (200μmol/L) increases the effection moreobviously.Compare with mustard aldehyde and coniferyl aldehyde treatment on same concentration,wefound feeding with mustard aldehyde processing have an higher gene expression amount.So treating withmustard aldehyde did a more significant influence on phenylpropanoid metabolic pathway related genesexpression.（4）Using the acetyl bromide method to biochemical analysis the different substrate feeding culture27days cotton fiber. The test results for the control group of lignin content was5.48%,200μmol/L treatmentthan mustard aldehyde1.27%lower than200μmol/L, coniferyl aldehyde treatment of low0.76%. TheSPSS software to analyze the correlation between the control group and coniferyl aldehyde,200μmol/Ltreatment reached significant level (P <0.05), and mustard aldehyde200μ mol/L treatment was verysignificant (P <0.01).In this experiment, using cultured ovule in vitro, exogenous mustard aldehyde and the coniferylaldehyde has an important influence on the growth and development of the cotton fiber which wasconfirmed from the growth morphology, relative quantification and chemical analysis perspective.Thisresult laid the foundation for further understanding of the mechanism of action of phenylpropanoidcompounds in cotton fiber development process.