Transgenic Elite Lines of Carioca Seeded Common Bean (Phaseolus Vulgaris L.) With Multiple Resistance to Viruses Reduce Cowpea Mild Mottle Virus Transmission

Abstract

The most important viruses infecting common bean (Phaseolus vulgaris L.) in Brazil are BCMV, BGMV and CPMMV, the last two transmitted by the whitefly Bemisia tabaci, occurring simultaneously and causing severe yield losses. Genetically modified progenies of common bean, from carioca market class and multiple virus resistance (BCMV, BGMV and CPMMV), have been developed using conventional breeding and molecular tools. Agronomic performance and virus disease severity (VS) evaluated in two field trials, selected 39 elite progenies out of 477. Molecular analyses identified the presence of BCMV and BGMV resistance alleles in plants. CPMMV resistance was measured on mechanically inoculated plants using a VS scoring scale. Among the lowest VS average scores, five progenies showed resistance to BCMV, BGMV and CPMMV, and upright plant architecture, resistance to plant lodging and carioca market class grains, presenting potential to be developed into a new transgenic cultivar, with multiple virus resistance. Additionally, the resistant progenies may also contribute to reduce virus spread in the field, as they were a less efficient inoculum source of CPMMV in insect transmission assays.