Genetic diversity, mating types and phylogenetic analysis of Indian races of <i>Fusarium oxysporum</i> f. sp. <i>ciceris</i> from chickpea

<p>The present study describes the comparative analysis of five genetic markers viz., random amplified polymorphic DNA (RAPD), enterobacterial repetitive intergenic consensus (ERIC), BOX-elements, mating type (MAT) locus and microsatellites for genetic analysis of virulent isolates of <i>Fusarium oxysporum</i> f. sp. <i>ciceri</i> (FOC) representing seven races from chickpea. Phylogenetic analysis of translation elongation factor 1-α and internal transcribed spacer region separated all the FOC isolates into two major clades. Majority of the isolates (FOC 63, FOC 33, FOC 40, FOC 100, FOC 6, FOC 22, FOC 31, FOC 79 and NDFOC 98) representing race 1, 2, 5 and 6 grouped in clade I, while isolates (FOC 90, FOC 108 and FOC 88) belonging to race 3, 4 and 7 were clustered in clade II. Isolates (FOC 33, FOC 40, FOC 17 and FOC 100) representing race 2 had MAT-2 loci, while race 1 isolates (FOC 63, FOC 72 and FOC 76) contained MAT-1 loci only. The principal component analysis (PCA) of RAPD, ERIC, BOX and microsatellite marker data explained 39.94, 39.98, 42.04 and 62.59% of the total variation among test isolates, respectively. Furthermore, there was no correlation existed between genetic diversity, virulence, race compositions or geographic origin of the isolates. Overall, these findings will assist in better understanding of the genetic variability and ideally, will improve disease management practices.</p

Table_1_Functional interplay between antagonistic bacteria and Rhizoctonia solani in the tomato plant rhizosphere.DOCX

Microbial interactions with plant roots play an imperial role in tomato plant growth and defense against the Rhizoctonia solani. This study performed a field experiment with two antagonistic bacteria (Pseudomonas and Bacillus) inoculated in healthy and Rhizoctonia solani treated soil in tomato rhizosphere to understand the metabolic pattern and microbial function during plant disease suppression. In the present study, we assessed soil and microbial enzymes, bacterial and fungal cell forming unit (CFU), and carbon utilization profiling through Bio-Eco plates of rhizoplane samples. Antagonist bacteria and pathogen interaction significantly (p < 0.05) influenced the bacterial count, soil enzymes (chitinase and glucanase), and bacterial function (siderophore and chitinase production). These results indicated that these variables had an imperial role in disease suppression during plant development. Furthermore, the metabolic profiling showed that carbon source utilization enhanced under fruit development and ripening stages. These results suggested that carbon sources were essential in plant/pathogen/antagonist interaction. Substrates like β-methyl-D-glucoside, D-mannitol, D-galacturonic acid, N-acetyl-D-glucosamine, and phenylethylamine strongly connect with the suppuration of root rot disease. These carbon sources may help to propagate a healthy microbial community to reduce the pathogen invasion in the plant root system, and these carbon sources can be stimulators of antagonists against pathogens in the future.</p