不同绿僵菌定殖水稻根系及其促生效应

Colonization and rice growth-promoting effects of different Metarhizium strains

摘要:

【背景】 绿僵菌(Metarhizium spp.)是一种重要的昆虫病原真菌，近年来发现它也可以定殖于植物根系促进植物生长，但对水稻生长的影响及促生机制尚不明晰。此外，不同种绿僵菌的定殖及促生效应的差异也有待研究。【目的】 明确罗伯茨绿僵菌(Metarhizium robertsii)和蝗绿僵菌(Metarhizium acridum)在水稻根内的定殖及对水稻生长影响的差异。【方法】 通过选择培养、显微镜观察、分子生物学鉴定确定罗伯茨绿僵菌和蝗绿僵菌在水稻根系的定殖情况，同时比较在土培和水培条件下两株绿僵菌对水稻种子萌发、株高、根长、鲜重、干重、叶绿素含量和根系活力的影响。【结果】 罗伯茨绿僵菌能够在水稻根内定殖并促进水稻种子萌发及生长。土培条件下，罗伯茨绿僵菌对水稻株高、根长、鲜重、干重、叶绿素含量和根系活力增效最高分别为45.2%、72.3%、30.5%、72.6%、92.3%和63.7%；水培条件下，对水稻株高、根长、鲜重、干重和叶绿素含量增效最高分别为59.3%、17.9%、90.9%、28.4%和64.8%。土培条件下，罗伯茨绿僵菌对水稻根长、干重和叶绿素含量增效高于水培条件，而株高和鲜重增效低于水培。【结论】 罗伯茨绿僵菌能够定殖在水稻根内并促进水稻生长，而蝗绿僵菌对水稻生长无显著影响，这为绿僵菌水稻促生机制的研究提供了一定的理论依据。

Abstract:

[Background] The recent studies have shown that Metarhizium spp., major entomopathogenic fungi, can colonize plant roots and promote plant growth. However, the effects and mechanisms of Metarhizium in promoting rice growth remain unclear. In addition, the colonization abilities and growth-promoting effects of different Metarhizium strains remain to be studied. [Objective] To clarify the colonization abilities and rice growth-promoting effects of M. robertsii and M. acridum. [Methods] The colonization abilities of M. robertsii and M. acridum were determined by selective culture, microscopic observation, and molecular methods. At the same time, the growth and physiological indexes of rice treated the two strains under soil cultivation and hydroponic cultivation conditions were compared, including the seed germination rate, plant height, taproot length, fresh weight, dry weight, chlorophyll content, and root vitality. [Results] Only M. robertsii colonized rice roots, accelerated the germination of rice seeds, and promoted the growth of rice. Under soil cultivation conditions, M. robertsii increased the height, taproot length, fresh weight, dry weight, chlorophyll content, and root vitality of rice plants by a maximum of 45.2%, 72.3%, 30.5%, 72.6%, 92.3% and 63.7%, respectively. Under hydroponic cultivation conditions, it increased the plant height, taproot length, fresh weight, dry weight, and chlorophyll content by a maximum of 59.3%, 17.9%, 90.9%, 28.4%, and 64.8%, respectively. M. robertsii exerted stronger promoting effects on the root length, dry weight and chlorophyll content of rice plants in soil cultivation than in hydroponic cultivation, while it demonstrated stronger promoting effects on the plant height and fresh weight of rice plants in hydroponic cultivation than in soil cultivation. [Conclusion] M. robertsii could colonize rice roots and promote the growth of rice, whereas M. acridum had no significant effect on the growth of rice. The findings provide a theoretical basis for deciphering the rice growth-promoting mechanism of Metarhizium.