Increased Resistance to Penicillium Sp. Seed Rot In Transgenic Wheat Over-Expressing Puroindolines.

Puroindolines are the main components of the wheat grain hardness locus (Ha) and have in vitro antimicrobial activity against bacteria and fungi. Here we examined the effect of variation in PINA and/or PINB content upon seed fungal growth inhibition. The two pathogens tested were Penicillium claviforme and Rhizoctonia solani. The P. claviforme assays were germination assays performed after incubating seeds in P. claviforme contaminated soil. The R. solani assays tested the antifungal capacity of TX-114 extracts from wheats varying in PIN content. The first set of wheat genotypes consisted of two sets of transgenic isolines created in the varieties ‘Bobwhite’ and ‘Hi-Line’ having over-expression of PINA and/or PINB. The second set of genotypes consisted of near isogenic lines (NILs) created in the varieties ‘Explorer’ and ‘Hank’ that varied. After incubation in P. claviforme infected soil, transgenic wheat seeds over-expressing PINA in both ‘Hi-Line’ and ‘Bobwhite’ and both PINS in ‘Hi-Line’ exhibited significantly reduced fungal infection and increased germination. This result was consistent with reduced growth of R. solani on Petri plates containing PINA extracts. No significant differences in P. claviforme infection or germination rates were observed in seeds of the ‘Explorer’ and ‘Hank’ NILs. The results indicate that Puroindolines native role in seeds is to increase seed viability and that when over-expressed as transgenes, the Puroindolines are effective antifungal proteins.