高抗黄萎病的低酚棉种质系中5629的选育与抗性机理研究

Studies on the Breeding for Z5629, a Glandless Cotton Germplasm with Resistant to Verticillium dahliae and Its Resistant Mechanism

通过多年连续病圃定向筛选,从感黄萎病品系中421中培育成高抗黄萎病低酚棉种质系———中5629。以中5629及其遗传背景品种(中421)、3个抗病品种和3个感病品种(系)为材料,比较分析中5629的植株组织结构、酶活性和根系分泌物种类含量,研究该种质系的黄萎病抗性机制。结果表明,中5629根和茎的导管细胞壁厚、导管直径小、导管数目和髓射线数目多、单位面积薄壁细胞数多。接种黄萎病菌后,中5629叶片中的苯丙氨酸解氨酶(PAL)活性显著高于其遗传背景品种及其它参试品种,为特有的生物代谢特征。中5629根系分泌物中只检测到丝氨酸、甘氨酸、缬氨酸、蛋氨酸、酪氨酸和精氨酸等6种氨基酸,株氨基酸总含量为3.05μg,显著低于其遗传背景品种。中5629中的根系分泌物中的葡萄糖、果糖和蔗糖含量均显著低于其遗传背景品种。

A glandless cotton germplasm named Z5629 with high resistantce to Verticillium dahliae was derived through the method of direction and continuous selection in the disease nursery. The mechanism of its resistance to Verticillium dahliae was studied via the compared analysis of the plant anatomical structure, PAL activity and root exudates in the plants in the different time of inoculation with Verticillium dahliae, an Anyang strain with intermediate virulent, using its genetic background line and other six resistant and susceptive upland cotton cultivars as check. The results showed that there were more pith rays, xylem parenchyma cells, and vessels with thicker wall and smaller diameter in Z5629 stem and taproots, comparing with its genetic background line. The PAL activity was increased in the Z5629 much more greatly after inoculation than that in its genetic background line and other resistant and/or susceptive cultivars, which was a very special character might relate to its resistance. There were only six amino acids, namely serine, glycin, valine, methionine, tyrosine, and arginine, with a total content of 3.05 μg per plant, in Z5629 root exudates, which were much less than that in its background line. The saccharide types in the root exudates were no different between two materials, but the contents of glucose, fructose and sucrose in Z5629 root exudates were much lower than those in its background line.