Expression And Functional Analyses Of Arabidopsis CesA Genes Under Light/Dark Treatments

Concerns about natural resource shortage, energy crisis and globe warming have been seriously raised over the world. As an ideal way, application of lignocellulose-based biofuels is currently considered for the energy supply and environmental protection. Cellulose is the most abundant renewable biomass on the earth and is also major component of the plant cell walls. Understanding of cellulose biosynthesis is thus important scientifically. In this study, I attempted to characterize Arabidopsis cellulose synthase genes （CesAs） under light/dark treatments. The major results described below:3. Genetic identification of AtCesA6 T-DNA mutantsT1 seeds of AtCesA6 T-DNA insertion mutant （salk₀04587） lines were obtained from Arabidopsis Biological Resource Center. The mutant homozygous was identified by PCR method. Its mRNA expression level was not much altered compared with the wild type in four stages of plant growth and development. The T-DNA sequence in the mutant was also transcripted into mRNA level.4. Expression analysis of AtCesAs under light/dark treatmentsExpression analysis showed that AtCesA1, AtCesA3, AtCesA2, AtCesA5 and AtCesA6 had similar expression patterns in 9-day-old light-grown seedlings. Compared with wild type, however, the five genes’transcript levels under light condition were decreased in Atcesa6 and prc1-1 mutants. Under dark treatment, AtCesAl and AtCesA6 transcript levels were reduced in both mutantst, but other three genes show unchanged.5. Analysis of Cell wall composition analysis under light/dark conditionseThe results showed that Atcesa6 and prc1-1 mutants, under dark condition, had a reduced cellulose and increased pectins in comparison with wild type. Under light, mutants and wild type both showed a similar cell wall composition in their seedlings.6. Morphological observation of mutants under DCB and CGA325’615 treatmentsAtcesa6 mutants showed a remarkable resistance to DCB and tolerance to CGA compared with wild type.7. Vector construction of AtCesAs genes for over-expressionI constructed vectors for AtCesAl, AtCesA2 and AtCesA5 over-expression. AtCesAl and AtCesA5 transgenic plants were selected and AtCesA2 transgenic plants are under screening.