Trichoderma asperellum (T42)-mediated expression of CabHLH genes enhances nitrogen use efficiency and nutritional values of chickpea under salt and Fusarium wilt stresses

Abstract

Trichoderma asperellum T42 combats diverse phytopathogens and other stresses. However, its impact under combined stresses in modulating nutritional value and antioxidant properties in edible plant parts has not been thoroughly studied. Three chickpea cultivars, viz., wilt-resistant (JG-315), wilt-tolerant (JG-36), and wilt-susceptible (JG-62), were used to assess nutritional value and antioxidant contents under salt and pathogen (Foc)-challenged conditions. A sharp decrease in nodule numbers and biomass was observed in plants challenged with the combined stresses of Foc and salt in all three cultivars. However, seed treatment with T42 restored the nutritional value, enhanced antioxidant activities (1–2 folds) and increased total phenolic content (1.3–1.5 folds), protein (19–28%), proline, and micronutrients (7–28%) in chickpea seeds, particularly in the T42-treated plants subjected to the combined stress compared to the plants subjected to the combined stress without T42. The expression of two chickpea bHLH transcription factor genes, CabHLH114 and CabHLH115, associated with nodule development and nitrogen fixation, varied under different stresses. The genes were upregulated in T42-treated plants and correlated with the development of root nodules. The results thus suggest that Trichoderma-mediated expression of both nodulation-responsive genes led to the formation of healthy and functional nodules, which helped improve nitrogen use efficiency in the chickpea plants and contributed to the nutritional value of the chickpea seeds. The results highlighted that reduction in nutritional value due to environmental stresses could be restored in crop plants by applying potential bioagents such as T42 that restore nutritional quality and make the crops climate resilient.