The role of Trichoderma koningii and Trichoderma harzianum in mitigating the combined stresses motivated by Sclerotinia sclerotiorum and salinity in common bean (Phaseolus vulgaris)

•The role of two salinity-tolerant Trichoderma isolates, T. harzianum and T. koningii, have been investigated in alleviating the dual stress, S. sclerotiorum and salinity on common bean seedlings.•The in vitro study showed high tolerance of T. harzianum and T. koningii to salinity which both isolates could grow and sporulate on saline media.•Both isolates showed high antagonism against S. sclerotiorum, and produced highly active cell wall lytic enzymes, chitinase, and cellulose, under high salinity stress.•T. harzianum was more powerful due to the presence of amylase and proteinase (Prb1) genes; these could give higher affinity to highly affect the pathogen in the presence or absence of salinity besides inducing the resistance against salinity stress.•T. harzianum is more beneficial than T. koningii in the up-regulation of various physiological processes, especially for combined stress.•The greenhouse experiment confirmed the successful role of T. harzianum and T. koningii in suppressing the stress of S. sclerotiorum and salinity and improving common bean seedlings' physiological traits compared to untreated seedlings.•Both Trichoderma isolates induced the resistance of stressed common bean seedlings by stimulating photosynthetic pigment, salicylic acid, hydrogen sulfide secondary metabolites, and antioxidants which aided in restricting oxidative and nitrosative stresses and membrane damage criteria.