樟子松根部深色有隔内生真菌的生防菌筛选

Screening of biocontrol fungi for dark-colored endophytic fungi in the roots of Pinus sylvestris var. mongolica

【目的】以樟子松根部深色有隔内生真菌(Dark Septate Endophytes,DSE)的分离鉴定和抗病促生菌株的筛选为目标,验证其对于樟子松的抗病性及生长发育的影响,为进一步研究深色有隔内生真菌-樟子松互作抗病机制打下基础。【方法】采用形态学鉴定和分子生物学技术相结合的方法,对樟子松根内深色有隔内生真菌进行了分离、鉴定,然后通过对峙培养和发酵液抑菌实验筛选抑制立枯丝核菌(Rhizoctonia solani)的高效生防菌株,以及将深色有隔内生真菌接种到一年生樟子松苗上测定其对樟子松的促生作用。【结果】共分离得到24株DSE菌株,主要包括Phialocephala bamuru、Phialocephala fortinii、Alternaria tamaricis、Paraphoma chrysanthemicola、Paraphoma radicina等。对峙培养条件下A024、A002对立枯丝核菌抑制效果最好,达到74.69%和71.20%,其中A024对立枯丝核菌的相对抑制效果达到22.47%,在抑制立枯丝核菌生长的同时,自身菌落生长未受到限制。发酵液抑菌实验中,抑制效果最好的菌株包括A024、A083和A002,抑制率分别为69.41%、64.11%和54.11%,可有效抑制立枯丝核菌菌丝的生长。樟子松一年生苗接种实验,菌株A003、A024对樟子松表现出较好的促生作用,同对照相比苗高、地径和生物量分别提高21.34%和15.40%、34.14%和30.67%、70.52%和35.85%。【结论】通过筛选得出的深色有隔内生真菌菌株A024对立枯丝核菌的抑制效果显著,且菌株A024和A003显著促进樟子松苗木的生长发育。本研究可为进一步研究深色有隔内生真菌-樟子松互作抗病机制提供理论依据和实践基础。

【Objective】The purpose of this study was to isolate and identify dark septate endophytes(DSE)from the roots of Pinus sylvestris var.mongolica and to screen the resistant and growth promoting strains to verify the effects of DSE on disease resistance and growth of Pinus sylvestris var.mongolica,so as to lay a foundation for further study on the interaction mechanisms for disease resistance of dark septate endophytes and Pinus sylvestris var.mongolica.【Method】The dark septate endophytic fungi in the roots of Pinus sylvestris var.mongolica were isolated and identified by morphological identification and molecular biology techniques.Then,the effective biocontrol strains against Rhizoctonia solani were screened by the confrontation culture and fermentation liquid bacteriostatic test.The growth-promoting effect of dark septate endophytic fungi on annual Pinus sylvestris var.mongolica seedlings was determined.【Result】A total of 24 DSE strains were isolated,including Phialocephala bamuru,Phialocephala fortinii,Alternaria tamaricis,Paraphoma chrysanthemicola,Paraphoma radicina,etc.A024 and A002 had the best inhibitory effects on Rhizoctonia solani under the conditions of confrontation culture,reaching 74.69%and 71.20%.Among them,the relative inhibitory effect of A024 on Rhizoctonia solani reached 22.47%.While inhibiting the growth of Rhizoctonia solani,the growth of its own colony was not restricted.In the fermentation broth antibacterial experiment,the strains with the best inhibitory effects included A024,A083 and A002,which inhibition rates were 69.41%,64.11%and 54.11%,which could effectively inhibit the growth of Rhizoctonia solani.In the inoculation experiment of annual seedlings of Pinus sylvestris var.mongolica,strains A003 and A024 showed good growth-promoting effects on Pinus sylvestris var.mongolica.Compared with the control,the seedling height,ground diameter and biomass of the seedlings increased by 21.34%and 15.40%,34.14%and 30.67%as well as 70.52%and 35.85%,respectively.【Conclusion】The dark-colored endophytic fungal strain A024 obtained by screening has a significant inhibitory effect on Rhizoctonia solani,and the strains A024 and A003 significantly promote the growth and development of Pinus sylvestris var.mongolica seedlings.This study can provide a theoretical and practical basis for further research on the disease resistance mechanism of dark septate endophytic fungi-Pinus sylvestris var.mongolica interaction.