Isolation and characterisation of plant growth-promoting bacterial and fungal endophytes from Himalayan Yew (Taxus wallichiana) - an economically imperative pant of Himalayas

It is a known fact that the bacterial and fungal endophytes inhabit the plant tissues besides aiding in the better growth and health of the plants. The bark and leaves of Taxus wallichiana have drawn a lot of interest in recent years since they are the richest source of taxol, an anticancer drug. As it is a slow-growing tree that can only be regenerated via vegetative propagation, it has been classified as a critical rare species due to its extensive collection for medicinal and other purposes. Nonetheless, the use of endophytes as plant growth promoters is gaining much importance among environmentalists and agronomists because of their imperative role in crop production. Even then, there is hardly any information available regarding the growth-promoting endophytes isolated from bark and leaves associated with T. wallichiana commonly known as Himalayan Yew. Therefore, the present study was undertaken to isolate fungal and bacterial endophytes from T. wallichiana and to classify the growth-promoting properties of these endophytes. In total, seven fungal and ten bacterial endophytes were obtained from different parts of T. wallichiana. All of the isolated fungal and bacterial endophytes produced indole acetic acid while most of them also produced ammonia. Besides, the fungal and bacterial endophytes were also screened for antimicrobial and various enzymatic activities. Based on the above results, the two fungal endophytes were selected for their possible ability to promote seed growth. The results showed that the fungal endophytes isolated from T. wallichiana played an active role in increasing growth in other plant species and therefore, can be used as potential plant growth promoters

Microbes mediated induced systemic response in plants: A review

Biotic stress affects economically important crop species and leads to quality and yield losses. Plants exhibit the ability of responding to the pathogen attack by synthesizing compounds which leads to either the inhibition or reduction of disease incidence. Plants live in close association with microbial communities. Microbes and their metabolites impact the health of the plants by supplying mineral nutrients, hormonal modulation and protection from the pathogenic organisms. Induced systemic response is one of the major mechanisms employed by the microbes in biocontrol. Beneficial microbes release certain compounds as elicitors in the rhizospheric region which are perceived by the plant roots as signals that increase the defense and resistance of the plants against the phytopathogens. The phytohormones such as ethylene, jasmonic acid, and salicylic acid are involved in regulation of the induced defense responses. The present review highlights the negative impact of the biotic stress on the plants and how induced systemic response is induced in the plants further discussing the role of the microbial elicitors in induced systemic response, their molecular mechanisms and hormonal regulation and draws the attention of the scientific community to explore new microbial elicitors as disease control alternatives