Plant viral diseases are major constraints causing significant yield losses worldwide in agricultural and horticultural crops. The commonly used methods cannot eliminate viral load in infected plants. Many unconventional methods are presently being employed to prevent viral infection; however, every time, these methods are not found promising. As a result, it is critical to identify the most promising and sustainable management strategies for economically important plant viral diseases. The genetic makeup of 90 percent of viral diseases constitutes a single-stranded RNA; the most promising way for management of any RNA viruses is through use ribonucleases. The scope of involving beneficial microbial organisms in the integrated management of viral diseases is of the utmost importance and is highly imperative. This review highlights the importance of prokaryotic plant growth-promoting rhizobacteria/endophytic bacteria, actinomycetes, and fungal organisms, as well as their possible mechanisms for suppressing viral infection in plants via cross-protection, ISR, and the accumulation of defensive enzymes, phenolic compounds, lipopeptides, protease, and RNase activity against plant virus infection.

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The prevalence and distribution of pathotypes and mating types of Ascochyta rabiei (Pass.) Labr. in India was evaluated during the winter (October to March) seasons of 2017-18 and 2018-19. Forty-five A. rabiei isolates were obtained from six different states. From the survey, the state of Punjab recorded the highest disease rating (Rating 9) compared to other chickpea growing areas. The β-tubulin gene was amplified (330 bp) from all the isolates, and sequence analysis was performed. The phylogenetic tree produced by cluster analysis of β-tubulin gene sequences differentiated the 44 A. rabiei isolates. Using multiplex PCR, mating types were identified. From the mating type (MAT) study of all isolates, amplification was observed at 490 bp which corresponds to mating type 2 (MAT1-2). The four pathotypes (I, II, III, IV) and six physiological races were delineated. The most predominantly distributed pathotype was pathotype III (52.27%) among the surveyed regions except Uttarakhand (where only pathotype II recorded), followed by the least aggressive pathotype I (22.7%), highly aggressive pathotype IV (15.9%) and aggressive pathotype II (9.1%). Among the six physiological races identified, most predominant races were race 5 (25%) followed by race 1 (22.73%), race 6 (18.18%), race 4 (18.18%), race 3 (9.09%) and race 2 (6.82%). Because of the prevalence of a single mating type among the surveyed locations, we opine that there may be less diversity in A. rabiei compared to isolates reported from other countries. However, to substantiate this conclusion, evaluation of higher number of isolates of A. rabiei is required.