MOLECULAR CHARACTERIZATION AND PATHOGENESIS OF Fusarium ASSOCIATED TO WHEAT YELLOWING

Abstract

Yellowing or early maturity of wheat (Triticum aestivum L.) is a disease caused by a complex of Fusarium species that may attack any part of the plant. This problem has been reported in several municipalities of the state of Guanajuato, México since the year 2000. This study isolated, characterized and identified the Fusarium species associated with the yellowing or early maturity of wheat in eight localities of Guanajuato; it also quantified their pathogenicity. One hundred and sixteen isolates from different organs of plants with symptoms were molecularly characterized by using ITS-RFLP, ISSR and identified with EF1-α gene sequences. The RFLP fragments from the ITS region and the ISSR technique produced different clusters. EF1-α gene sequences closely identified the isolates with the species F. proliferatum, F. subglutinans, F. oxysporum, F. thapsinum, and F. andiyazi. A wide severity range was observed in the pathogenicity tests (from 2.2 to 39.7 %). The highest aggressiveness was identified in strain T5.10 (F. proliferatum), as well as in a combined effect of strains R8.5 (F. proliferatum) and E5.3 (unidentified).