Specific antibody production using recombinant proteins to elucidate seed transmission and nuclear localization of Coguvirus citrulli and Coguvirus henanense in radicles of watermelon crop.

Watermelon crinkle leaf-associated virus 1 (WCLaV-1) and WCLaV-2, both belonging to the genus Coguvirus (family Phenuiviridae), have been identified in watermelon plants in Brazil. To study tissue tropism and the potential for seed transmission of these viruses, we initially planned to produce specific antibodies. However, difficulties in isolating and propagating the virus in host plants hindered the purified virus preparations. To overcome this problem, the nucleocapsid (N) proteins of WCLaV-1 and -2 were produced using the pepper ringspot virus vector. The N protein genes and the vector backbone were prepared by (RT-)PCR and ligated by Gibson assembly. The constructs were agro-infiltrated in Nicotiana benthamiana plants. The expressed N proteins were purified and used for polyclonal antibody production. The specificity of both antibodies was confirmed by antigen-coating ELISA, tissue-blot immunobinding assay and Western blot. By antigen-coating ELISA demonstrated that WCLaV-1 showed 93.1% of seed-transmission, while WCLaV-2 showed only 17.8%. The N protein of WCLaV-1 was detected in the cytoplasm of the seed tissues. It was also found in the nuclei of the radicle, as confirmed by confocal microscopy. We concluded that the antibodies exhibited both a high titer and sufficient specificity for use in ELISA-based diagnostics and for subcellular localization study.

Intensity of angular leaf spot and anthracnose on pods of common beans cultivated in three cropping systems / Intensidade da mancha-angular e da antracnose em vagens de feijão em três sistemas de cultivo

With the purpose to evaluate the intensity of angular leaf spot (ALS) and anthracnose (ANT) on pods, nine genotypes of common bean were planted in three cropping systems: monocrop (MC), monocrop grown on trellises (MCT), and intercrop with maize (ICM). In MC, beans were planted 0.5 m apart. Trelisses were set up with 1.8 m high bamboos and beans were sown 0.65 m apart. In ICM, beans were planted simultaneously with maize and in its rows. This cereal was sown 1.0 m apart with four plants per meter. Each cropping system was an independent trial installed close to each other. Climbing genotypes of beans most susceptible to ALS had less diseased pods in ICM than in both MC and MCT, but the less susceptible genotypes, regardless of their growth type, as well as the susceptible bush and semiclimbing genotypes, were similarly attacked by ALS in the three systems. ANT on pods of the susceptible bean cv. Pérola was less intense in MCT than in MC, and less intense in ICM than in MCT. ANT seed transmission was 11 percent, 9.1 percent, and 4.4 percent when seeds come from MC, MCT, and ICM, respectively.

Com o objetivo de avaliar a intensidade da mancha-angular (MA) e da antracnose (ANT) em vagens, nove genótipos de feijão foram plantados em três sistemas de plantio: monocultivo (MC), monocultivo com tutoragem artificial (MCT) e consórcio com milho (CCM). No MC, o feijão foi semeado no espaçamento entre fileiras de 0,50 m. Para o MCT, utilizaram-se varas de bambu formando "Vs" invertidos com 1,8 m de altura, nos quais foi mantido o espaçamento entre fileiras de 0,65 m na base. No CCM, o feijão foi plantado simultaneamente ao milho e em suas fileiras. Esse cereal foi semeado no espaçamento de 1,0 m, com quatro plantas por metro. Cada sistema de cultivo foi um ensaio independente, todos instalados na mesma área. Os genótipos trepadores mais suscetíveis à MA apresentaram menos vagens doentes no CCM que no MC e MCT, mas os genótipos menos atacados pela MA, independentemente do tipo de crescimento, como também os outros genótipos suscetíveis de porte anão e semitrepador, foram infectados de forma semelhante nos três sistemas de plantio. A ANT nas vagens do cv. Pérola foi menos intensa no MCT que no MC, e menos intensa no CCM que no MCT. A transmissão da ANT pela semente foi de 11 por cento, 9,1 por cento e 4,4 por cento quando as sementes foram colhidas no MC, MCT e CCM, respectivamente.