水分胁迫下内生真菌球毛壳ND35对冬小麦苗期生长和抗旱性的影响

为明确不同水分条件下内生真菌对冬小麦苗期生长和抗旱性的影响,以抗旱型小麦品种山农16和水分敏感型小麦品种山农22为材料,利用荧光定量PCR技术检测小麦干旱诱导基因脱水素wzy2的表达量来了解冬小麦在干旱胁迫下相关基因的表达差异,通过测定相关生理指标与酶活性来判断小麦发育及其在干旱胁迫下的生理响应状况。结果表明,与正常水分ND35组相比,接种球毛壳菌(Chaetomium globosum)ND35的干旱处理组小麦的根冠比、总蛋白含量、脯氨酸含量及丙二醛含量等指标显著提高,小麦叶片含水量和可溶性糖含量有所降低。在干旱处理组中,球毛壳菌ND35可以显著提高小麦山农16的根长和山农22的株高,接种球毛壳ND35的山农16脯氨酸含量、可溶性糖含量、过氧化氢酶活性比对照组均显著提高,丙二醛含量比对照组降低9.0%,但差异不显著;山农22脯氨酸含量和过氧化氢酶活性比对照组显著提高,丙二醛含量和可溶性糖含量比对照组有所降低,但可溶性糖含量差异不显著;相对定量检测数据显示,接种球毛壳ND35后,两种小麦脱水素wzy2基因的表达量较对照组均能够显著提高。综合分析说明内生真菌球毛壳ND35可以促进冬小麦苗期根系和植株发育,小麦提前进入三叶期,增强小麦避旱性,同时提高小麦根系活力,增强小麦耐旱性;提高个体细胞内水分、糖分、脯氨酸含量,降低丙二醛的氧化性损伤,增强过氧化氢酶活性,从而提高两种冬小麦对干旱胁迫的耐受能力;球毛壳ND35促进小麦干旱诱导相关基因wzy2的表达量,进而提高抗旱相关蛋白的表达,从而提高两种冬小麦耐脱水性和对干旱胁迫的适应性。

Effect of the endophytic fungus Chaetomium globosum ND35 on the growth and resistance to drought of winter wheat at the seedling stage under water stress

Endophytes are microbes that live in plant tissues without substantively harming them selves.They are ubiquitous in most plant species, latently residing in or actively colonizing the tissues.To clarify the effect of endophytic fungus on the growth and resistance to drought of winter wheat at the seedling stage under different water conditions, two wheat varieties, Shannong No. 16 and Shannong No. 22, were used as test materials. The dehydrin wzy2 belonging to the dehydration-responsive encoding gene was detected to master different expression of winter-wheat-related genes under drought stress by using a fluorescence quantitative PCR technique. The growth and development of plant and physiological responses under drought stress were investigated by measuring the related physiological indicators and enzyme activity. The results showed that, compared with ND35 groups treated with the normal water, Chaetomium globosum ND35 could significantly improve root-shoot ratio, proline content, protein content, and malondialdehyde (MDA) content of two wheat varieties in the drought group. The water content and soluble sugar content of leaves were reduced slightly in two wheat varieties. In the drought treatment group, C. globosum ND35 could promote root growth of Shannong No. 16 and increase the plant height of Shannong No. 22. The proline content, soluble sugar content, and catalase (CAT) activity of Shannong No. 16 treated with C. globosum ND35 group were increased more than in the control group, while the MDA was reduced by 9.0%. Proline and CAT activity increased and there was an indistinctive difference in soluble sugar content in Shannong No. 22, while the MDA content was reduced. The relative quantitative expression of wzy2 gene was examined. The results showed that dehydrin gene expression in the two wheat varieties inoculated with C. globosum ND35 was increased significantly, compared with that of the control group. Above all, the endophytic fungus C. globosum ND35 could promote seedling root and plant growth, the wheat could develop into three-leaf stage earlier, and resistance to dehydration was enhanced. In addition, wheat root vigor was improved and resistance to drought was increased. The individual water content, sugar content, and proline content in cells were increased, oxidative damage caused by malondialdehyde was reduced, and the activity of catalase was enhanced, thus improving wheat tolerance to drought stress. The expression of related genes wzy2 in quantity was obviously increased in wheat inoculated with C. globosum ND35, and then the expression of resistance to drought-related proteins was improved. As a result, resistance and adaptability to drought stress were improved in winter wheat plants.