75种植物乙醇提取物对两种土传病原菌的抑制活性OA

[Objective]Soil-borne disease has become a prevalent and intractable issue in current agricultural production,while the existing chemical control agents often lead to pesticide residues and phytotoxicity to crops.In contrast,botanical fungicides possess distinct advantages,including broad-spectrum inhibitory activity,environmental friendliness,as well as easy metabolism and degradation in the ecosystem.This study aimed to target two typical soil-borne pathogens(Phytophthora capsici and Fusarium oxysporum f.sp.niveum),determine the inhibitory activities of extracts from 75 tested plants,and to screen out plant resources with high activity,thereby laying a foundation for the development of novel botanical fungicides.[Method]The growth rate method was employed to determine the inhibitory activities of ethanol extracts of 75 kinds of plants against P.capsici and F.oxysporum f.sp.niveum.The pot efficacy of the screened high-activity extracts against pepper phytophthora disease and watermelon fusarium wilt was determined by means of the root irrigation and the root injury method.[Result]The mycelial inhibition rates of five ethanol extracts of Magnolia officinalis,Notopterygium incisum,Syringa pinnatifolia,Platycladus orientalis and Ilex chinensis against P.capsici were over 60%at the concentration of 1 mg·mL-1.The inhibition rates of 11 other ethanol extracts,including Rubia cordifolia and Lindera aggregata,ranged from 30%to 60%,while the remaining 59 extracts showed no significant inhibitory activity.Among them,the ethanol extract of M.officinalis had the highest toxicity against P.capsici,with EC50 of 0.023 mg·mL-1.The mycelial inhibition rates of three ethanol extracts of M.officinalis,Ligusticum chuanxiong and Curcuma longa against F.oxysporum f.sp.niveum were over 60%at the concentration of 1 mg·mL-1.The inhibition rates of 12 other ethanol extracts,such as Alpinia officinarum and S.pinnatifolia,were between 30%and 60%,and the remaining 60 extracts displayed no significant inhibitory activity.Among them,the ethanol extract of C.longa had the highest toxicity against F.oxysporum f.sp.niveum,with EC50 of 0.606 mg·mL-1.Pot efficacy results showed that the ethanol extract of M.officinalis exhibited high protective and curative efficacy against pepper phytophthora disease at the concentration of 8 mg·mL-1,with efficacy rates of 64.74%and 63.25%,respectively.The ethanol extract of S.pinnatifolia showed high curative efficacy against pepper phytophthora disease at the concentration of 8 mg·mL-1,with efficacy rate of 63.14%.However,the efficacy of both extracts was lower than the control fungicide shenqinmycin(protective efficacy:81.05%;curative efficacy:73.72%).The ethanol extract of C.longa showed high protective efficacy against watermelon fusarium wilt at the concentration of 8 mg·mL-1,with efficacy rate of 69.94%,which was comparable to the control fungicide carbendazim(66.65%).When applied at 2 mg·mL-1,this extract demonstrated a high curative efficacy against watermelon fusarium wilt,with efficacy rate of 78.08%,which was better than the control fungicide carbendazim(62.42%).In contrast,the efficacy of A.officinarum ethanol extract against watermelon fusarium wilt was less than 50%at all tested concentrations.[Conclusion]Ethanol extracts from S.pinnatifolia,C.longa,and M.officinalis exhibit potent inhibitory activities against soil-borne pathogens,which provides a scientific basis for the subsequent development of new botanical fungicides.