Whitefly-tolerant transgenic common bean (Phaseolus vulgaris) line

Abstract

Common bean (Phaseolus vulgaris L.) is a staple food in Brazil with both nutritional and socioeconomic importance. As an orphan crop, it has not received as much research attention as the commodity crops. Crop losses are strongly related to virus diseases transmitted by the whitefly Bemisia tabaci, one of the most important agricultural pests in the world. The main method of managing whitefly-transmitted viruses has been the application of insecticides to reduce vector populations. Compared to chemical vector control, a more sustainable strategy for managing insect-borne viruses is the development of resistant/tolerant cultivars. RNA interference has been applied to develop plant lines resistant to the whitefly in other species, such as tomato, lettuce and tobacco. Still, no whitefly-resistant plant has been made commercially available to date. Common bean is a recalcitrant species to in vitro regeneration; therefore, stable genetic transformation of this plant has been achieved only at low frequencies (<1%) using particle bombardment. In the present work, two transgenic common bean lines were obtained with an intron-hairpin construct to induce post-transcriptional gene silencing against the B. tabaci vATPase (Bt-vATPase) gene, with stable expression of siRNA. Northern blot analysis revealed the presence of bands of expected size for siRNA in leaf samples of the line Bt-22.5, while in the other line (11.5), the amount of siRNA produced was significantly smaller. Bioassays were conducted with both lines, but only the line Bt-22.5 was associated with significant mortality of adult insects (97% when insects were fed on detached leaves and 59% on the whole plant). The expression of the Bt-vATPase gene was 50% lower (p < 0.05) in insects that fed on the transgenic line Bt-22.5, when compared to non-transgenic controls. The transgenic line did not affect the virus transmission ability of the insects. Moreover, no effect was observed on the reproduction of non-target organisms, such as the black aphid Aphis craccivora, the leafminer Liriomyza sp. and the whitefly parasitoid Encarsia formosa. The results presented here serve as a basis for the development of whitefly-tolerant transgenic elite common bean cultivars, with potential to contribute to the management of the whitefly and virus diseases.

Major viral diseases in grain legumes: designing disease resistant legumes from plant breeding and OMICS integration

“…Inserting a 302 bp inverted repeat of the P3 cistron, isolated from SMV strain SC3 resulted in RNAi-mediated genetically engineered soybean lines with stable resistance against multiple virus strains of SMV, BCMV, and WMV ( Yang et al., 2018 ). RNAi strategies have also been used to combat bean golden mosaic virus (BGMV) in common bean by silencing the rep (AC1) viral gene ( Bonfim et al., 2007 ; Aragão et al., 2013 ; de Paula et al., 2015 ) and to prevent whitefly ( Bamicia tabaci ) infection by suppressing the ATPase (Bt-vATPase) gene in B. tabaci ( Ferreira et al., 2022 ). Thus, pathogen-derived transgenic resistance can be achieved using an RNAi strategy to develop virus resistance in legumes (see Figure 2 ).…”

New Biocompatible Technique Based on the Use of a Laser to Control the Whitefly Bemisia tabaci

“…The whitefly Bemisia tabaci MEAM1 biotype used in the experiments originated from a colony on common bean (Phaseolus vulgaris, cv. Pérola), kept under screen house conditions at Embrapa Arroz e Feijão, Santo Antônio de Goiás, GO, Brazil (16 • 28 00 S, 49 • 17 00 W; 823 m asl), as previously described [23,24]. To obtain age-synchronized adult insects, plants containing whitefly eggs laid for 2 h were isolated in insect cages, after removing the adults, until reaching the third larval instar.…”