Bacillus cabrialesii: Five Years of Research on a Novel Species of Biological Control and Plant Growth-Promoting Bacteria.

Bacillus cabrialesii is a novel bacterial species isolated from wheat (Triticum turgidum L. subsp. durum) plants in the Yaqui Valley, Mexico, by our research team. Over years of research studying this strain at the cutting-edge level, it has shown different mechanisms of action. B. cabrialesii is strongly reported as a plant-growth-promoting bacterium and a biological control agent on wheat crops. Knowing this, B. cabrialesii has been brought from lab to field as part of a bacterial consortium, not to mention that there are ongoing investigations into formulating a cost-effective bioinoculant to increase the yield and/or quality of wheat. Moreover, studies of this novel species as a biocontrol agent in other crops (pepper, tomato, cucumber, and potato) are being carried out, with preliminary results that make B. cabrialesii a promising biological control agent, inhibiting the growth of phytopathogens. However, research into this bacterium has not only been reported in our country; there are many studies around the world in which promising native Bacillus strains end up being identified as B. cabrialesii, which reaffirms the fact that this bacterial species can promote plant growth and combat phytopathogens, showing great agrobiotechnological potential.

Genetic diversity of Fusarium pseudocircinatum in the central western region of Mexico: the case of big-leaf mahogany malformation disease.

Fusarium pseudocircinatum is the main causal agent of big-leaf mahogany malformation disease (BLMMD) of mahogany (Swietenia macrophylla) in Mexico. Although, BLMMD is the most important disease for this high-value timber species, there is a lack of information on the genetic variation present in geographically diverse isolates of F. pseudocircinatum. The objective of this study was to determine the genetic diversity of populations of F. pseudocircinatum causing BLMMD in the central western region of Mexico. A total of 611 big-leaf mahogany trees were inspected at eight sites in four states (Colima, Guerrero, Jalisco and Michoacán); of these, 42.7% showed malformation symptoms similar to those of BLMMD. Of 374 Fusarium isolates that were recovered, 277 were identified as F. pseudocircinatum, 56 were F. mexicanum, and 41 were Fusarium spp. An ISSR analysis of the F. pseudocircinatum isolates generated 51 bands of which 38 were polymorphic (76.8%) with a mean of 17 bands per primer. A total of 87 multilocus genotypes (MLGs) were identified. Nei's genetic diversity analysis showed that the isolates had a high genetic diversity average (0.147), with values ranging from 0.070 to 0.365 depending of the geographical location. An analysis of molecular variance revealed that the variation within the populations was low (27.36%), while the variation within MLGs was significant (72.64%), indicating genetic flow. Overall, the genetic variability of F. pseudocircinatum populations was high and the MLGs from Colima (Colima) and Gabriel Zamora (Michoacán) were placed centrally, which possibly is evidence of ancestry and indicates its dispersion routes in the central western region of Mexico.