Differential expressed transcripts associated to chemical-induced male sterility by imidazolinone herbicide treatment in Imisun sunflower

NESTARES GRACIELA; FELITTI, S.; LOSTE NICOLÁS; OCHOGAVÍA, ANA

Mendoza

Congreso; ALAG 2019 XVII Congreso Latinoamericano de Genética, XLVII Congreso Argentino de Genética; 2019

Asociación Latinoamericana de Genética (ALAG) y Sociedad Argentina de Genética (SAG)

Imidazolinones (IMI) are herbicides that inhibit the acetohydroxyacid synthase activity. Imisun sunflowers (Helianthus annuus L.) are commercial IMI-resistant cultivars. A digenic model with a major gene Imr1 and a modifier gene Imr2 explains the genotypic resistance. IMI application during early reproductive growth stages was recently proposed as chemical agent for inducing male sterility in resistant sunflower. However, the underlying mechanism remains unknown. The aim of our work was to analyze the differential expressed genes in male reproductive tissue treated by twice the recommended field dose of imazapyr (160 g a.i. ha-1) in two Imisun genotypes: resistant (R; Imr1Imr1Imr2Imr2) and intermediate resistant (I; Imr1Imr1imr2imr2). Immature anthers were collected and fixed at 11, 13 and 16 days after treatment in order to be observed by Confocal Laser Microscopy (CLM) and analyzed by cDNA-AFLP. The treatment induced complete male-sterility in both R and I genotypes. CLM revealed cell damage in the sporogenous tissue during the microsporogenesis in treated plants of both genotypes, comprising 60-100% of the pollen sac section. The cDNA-AFLP analysis allowed to obtain 617 scorable transcript-derived fragments, and the 80% were differentially expressed between treated and control plants. Our results suggest that 2X IMI-treatment induced Imr2-independent response in anthers of Imisun sunflowers. The cDNA-AFLP analysis will contribute to the identification of the molecular bases of a novel chemical method for inducing male sterility in sunflower crop.