大蒜根际铁载体曲霉菌株的分离及其对番茄铁营养和抗病性的协同作用OA

To address the decline in plant disease resistance caused by soil iron deficiency,this study screened siderophore-high-yielding Aspergillus strains from garlic rhizosphere soil.The strains were identified through morphological observation and gene sequence analysis.The ability of the strains to produce iron carriers was determined using the Chrome Azurol S(CAS)qualitative-quantitative assay.Physiological indices in tomatoes such as biomass and chlorophyll content were employed using Hoagland's iron-deficient hydroponic system and pot experiments with different saline-alkaline soils.Furthermore,the antibacterial activity and control effects of the strains against tomato wilt disease were comprehensively evaluated through experiments such as plate confrontation,spore germination inhibition,tomato defense enzyme activity assays,and saline-alkaline soil prevention and controly.The results showed that two siderophore-high-yielding Aspergillus strains were isolated,namely Aspergillus neoniger YNAU-S1 and Aspergillus fumigatus YNAU-S2,with siderophore units(Su)of 79.30％and 65.47％,respectively.Whether in saline-alkaline or neutral soils,inoculation with YNAU-S1 can significantly alleviate iron-deficiency-induced chlorosis in tomatoes,promoted plant growth,and enhanced iron absorption.Antifungal tests revealed that YNAU-S1 and YNAU-S2 inhibited the mycelial growth of Fusarium oxysporum f.sp.lycopersici(FOL)by 75.02％and 73.22％,respectively.Further investigation demonstrated that iron-deficiency-induced fermentation broth significantly suppressed FOL spore germination and enhanced tomato plant resistance.Correlation analysis indicated there was a significant positive relationship between siderophore yield and resistance level.Under saline-alkaline soil pot conditions,the iron-deficiency-induced fermentation broth of YNAU-S1 promoted iron absorption in tomatoes while achieving a relative control efficacy of 80.77％against Fusarium wilt.In conclusion,the garlic rhizosphere Aspergillus strains synergistically regulate"iron nutrition supply-pathogen inhibition-resistance activation"through siderophore secretion,providing efficient candidate strains and a theoretical basis for improving iron nutrition and green control of soil-borne diseases in tomatoes grown in saline-alkaline soils.