Molecular diversity of seed-borne Fusarium species associated with maize in India

Abstract

<p>A total of 106 maize seed samples were collected from different agro-climatic regions of<br />India. Sixty-two Fusarium isolates were recovered, 90% of which were identified as Fusarium verticillioides<br />based on morphological and molecular characters. Use of the tef-1alpha gene corrected/refined<br />the morphological species identifications of 11 isolates, and confirmed those of the remaining isolates. Genetic diversity<br />among the Fusarium isolates involved multilocus fingerprinting profiles by Inter Simple Sequence Repeats (ISSR) UPGMA<br />and tef-1 alpha gene phenetic analyses; for which, we observed no significant differences among the isolates based on<br />geographic origin or fumonisin production; most of the subdivision related to species. Genotyping was performed on the<br />F. verticillioides isolates, using 12 primer sets from the fumonisin pathway, to elucidate the molecular basis of fumonisin<br />production or non-production. One fumonisin-negative isolate, UOMMF-16, was unable to amplify nine of the 12 fumonisin<br />cluster genes tested. We also used the CD-ELISA method to confirm fumonisin production for our 62 Fusarium<br />isolates. Only 15 isolates were found to be fumonisin-negative. Interestingly, genotypic characterization revealed six isolates<br />with various gene deletion patterns that also tested positive for the production of fumonisins via CD-ELISA. Our<br />findings confirm the importance of molecular studies for species delimitation, and for observing genetic and phenotypic<br />diversity, among the Fusaria.<br /></p>