| The wheat albinism line FA85 is a natural mutant strain from the parent dwarf wheat Aibian 1, which presents the "albino – return to green" features induced by low temperature in the winter and spring at seedling stage, and this phenomena lasts about 30 to 40 days.Previous studies showed that the application of plant hormone abscisic acid(ABA) can promote the chloroplast development and delay the albinism of FA85 leaves significantly. In order to investigate whether there are abnormities on endogenous ABA accumulation and ABA signal transduction in FA85, we developed an optimized SPE-LC-ESI-MS/MS method to assay the ABA content in FA85 and Aibian1 leaves, and analysed the expression of ABA related genes with gene chip, real-time quantitative PCR and semi-quantitative PCR. The conclusions are as follows:(1) There was no problem on endogenous ABA accumulation in FA85 at room temperature and low temperature. Exogenous ABA improved the endogenous ABA content in FA85.(2) The expression analysis of ABA related genes in FA85 and Aibian1 showed that the expression level of ABA receptor gene(CHLH), protein kinase genes(PKABA1 SnRK2.4),transcription factor genes(WABI5, ASR, ASR2), and ABA responsive protein genes(Wrab19,rab15B) were abnormal in FA85. These results indicated that the ABA signal transduction pathway was blocked in FA85 and the cold resistance in FA85 was decreased.(3) Exogenous ABA up-regulated the expression of CHLH, PKABA1 SnRK2.4, WABI5 ASR, ASR2 and ABA responsive protein gene rab15 B in FA85, which partially compensated the blocked ABA signal transduction pathway.To sum up, the accumulation of endogenous ABA in FA85 was normal, but the ABA signal transduction pathway was blocked in this albinism line. Exogenous ABA up-regulated the expression level of the positive regulatory factor genes in ABA signal transduction pathway, which probably improved the cold resistance in FA85 and postponed the albinism phenomena. |
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