Endophyte-Mediated Modulation of Defense-Related Genes and Systemic Resistance in Withania somnifera (L.) Dunal under Alternaria alternata Stress

Abstract

Endophytes have been explored and found to perform an important role in plant health. However, their effects on the host physiological function and disease management remain elusive. The present study aimed to assess the potential effects of endophytes, singly as well as in combination, in (L.) Dunal, on various physiological parameters and systemic defense mechanisms against Seeds primed with the endophytic bacteria and individually and in combination demonstrated an enhanced vigor index and germination rate. Interestingly, plants treated with the two-microbe combination showed the lowest plant mortality rate (28%) under stress. Physiological profiling of treated plants showed improved photosynthesis, respiration, transpiration, and stomatal conductance under pathogenic stress. Additionally, these endophytes not only augmented defense enzymes and antioxidant activity in treated plants but also enhanced the expression of salicylic acid- and jasmonic acid-responsive genes in the stressed plants. Reductions in reactive oxygen species (ROS) and reactive nitrogen species (RNS) along with enhanced callose deposition in host plant leaves corroborated well with the above findings. Altogether, the study provides novel insights into the underlying mechanisms behind the tripartite interaction of endophyte-- and underscores their ability to boost plant health under pathogen stress. is well known for producing several medicinally important secondary metabolites. These secondary metabolites are required by various pharmaceutical sectors to produce life-saving drugs. However, the cultivation of faces severe challenge from leaf spot disease caused by To keep pace with the rising demand for this plant and considering its capacity for cultivation under field conditions, the present study was undertaken to develop approaches to enhance production of through intervention using endophytes. Application of bacterial endophytes not only suppresses the pathogenicity of but also mitigates excessive ROS/RNS generation via enhanced physiological processes and antioxidant machinery. Expression profiling of plant defense-related genes further validates the efficacy of bacterial endophytes against leaf spot disease.

Induction of defense mechanisms involved in disease resistance of onion blight disease caused by Botrytis allii

“…Plants could be protected from the fungal infection by systemic induction of the encoding gene and pathogenesis-related protein. Expression of the gene-encoding phenylalanine ammonia-lyase (PAL) homolog can play a role in systemic plant resistance against the pathogens (Mishra et al 2018).…”

Plant responses underlying nonhost resistance of Citrus limon against Xanthomonas campestris pv. campestris

“…It has been observed that endophytic bacteria act by inducing priming and protecting plants against biotic and abiotic stress (Kandel et al ., ; Pavlo et al ., ). It has been reported that bacterial endophytes increase defence enzymes, such as PAL, and antioxidant activity, such as superoxide dismutase (SOD), and enhance callose deposition and SA‐responsive genes in host‐treated plants (Liu et al ., ; Mishra et al ., ).…”

Endophyte inoculation enhancesUlmus minorresistance to Dutch elm disease

“…Phenolic compounds are widely distributed in plants and play key roles in metabolic and physiological processes (Boudet, 2007). These molecules also have antioxidant properties (Huang et al, 2007) that can ameliorate plant performance under stress conditions (Daayf et al, 2012;Cheynier et al, 2013;Mishra et al, 2018). Several studies have demonstrated increased synthesis of flavonoids and phenols in plants colonized by symbiotic microorganisms (Qawasmeh et al, 2012;Dupont et al, 2015).…”