亚麻木质素合成关键酶基因表达分析

Expression of Critical Lignin Metabolism Genes in Flax(Linum usitatissimum)

以亚麻(Linum usitatissimum)栽培品种白花为材料,采用半定量RT-PCR方法对亚麻木质素合成关键酶基因CCoAOMT1、4CL1、4CL2、COMT、F5H1、F5H2和F5H3在不同组织及不同时期木质部、韧皮部的表达规律进行了研究。结果显示,除F5H1在根部未表达外,其他基因在幼苗、根、花期木质部、花期韧皮部、叶、花和幼果中均有不同程度表达。CCoAOMT1在各部位都有较高的表达。2个4CL之间和3个F5H基因之间的部位表达的差异存在一定互补性。在韧皮部中,各基因均在幼嫩(30d)阶段表达量最低;除4CL2在花期(60d)达到表达高峰外,其他基因均在花后(70d)表达量最高;4CL1在各时期均有较强表达,而F5H3在各时期弱表达。在木质部中,除4CL1在各时期均表达弱和F5H1在花前期为表达高峰外,其余基因均在幼嫩阶段表达量最高;随后逐渐降低,在花期后表达量大幅降低;4CL1的表达量明显区别于其他基因,其各时期韧皮部的表达量明显高于木质部。

Flax （Linum usitatissimum） is an important bast fiber crop. High lignin content in the flax fiber greatly affects the performance and quality in the flax textile industry. CCoAOMT1, 4CL1, 4CL2, COMT, F5H1, F5H2,and F5H3 are putative genes coding the key enzymes involved in lignin accumulation. Expression patterns of these genes were analyzed by semi-quantitative RT-PCRin different flax tissues and in xylem and phloem （bark） at different development stages of the variety Baihua. The results revealed that All genes were detected to express in seedlings, roots, florescent xylem, florescent phloem, leaves, flowers and young fruits excluding F5H1 in roots. Expression of CCoAOMT1 was consistently high in all the tissues detected. There existed complementary expression between two 4CL genesand among the three F5H genes in various tissues. In the phloem, all genes lowly expressed except for 4CL2 at florescence and highly expressed after flowering. Expression of 4CL1 was high, and that of F5H3 was low in the phloem at all stages compared with that of other genes. In the xylem, expression of 4CL1 gene was low at all the developing stages, that of F5H1 reached a peak before flowering and that of the other genes in the xylem reached the highest at 30 d after emergence of seedlings and gradually declined at late growing stages, with a sharp decrease to very lower level after flowering. The expression of 4CL1compared with other genes was significantly higher in phloem than in xylem.