Incidence of viruses infecting pepper in Thailand.

This study was conducted to determine the incidence, diversity and distribution of viruses infecting pepper (Capsicum spp.) in the central, northern and northeastern parts of Thailand. During a survey in 2016 - 2019, a total of 2,149 leaf samples from symptomatic and asymptomatic peppers were collected randomly from farmer's fields, and preliminary tested by an enzyme-linked immunosorbent assay (ELISA) using 7 antibodies specific for cucumber mosaic virus (CMV), chilli veinal mottle virus (ChiVMV), tomato necrotic ringspot virus (TNRV), tobacco mosaic virus (TMV), potato virus Y (PVY), tomato spotted wilt virus (TSWV), and begomoviruses. Our data revealed that the incidence of the viruses infecting pepper in Thailand was high, accounting for nearly 70% (1,482 infected samples). The highest viral incidence was found in the central part (96%), followed by the north (74.4%) and the northeastern (52.8%), respectively. Begomoviruses, CMV, ChiVMV, and TNRV were detected in the samples at varying rates, whereas PVY, TMV, and TSWV were not detected. Of these, the most frequently found virus was Begomoviruses accounting for nearly 33%, with the highest rate (ca. 82%) in the central Provinces of Thailand. In addition, of the 1,482 infected samples, mixed infections among the four viruses were also found in 616 samples (ca. 42%), and CMV + ChiVMV (approximately 11%) was the most common mixed infection. This is the first report describing an occurrence of viruses in pepper of Thailand, and the results obtained have revealed that viruses infecting pepper are widespread, which may pose a threat to pepper production in Thailand.

Identification and characterization of Pestalotiopsis-like fungi related to grapevine diseases in China.

Pestalotiopsis-like fungi are an important plant pathogenic genus causing postharvest fruit rot and trunk diseases in grapevine in many countries. Pestalotiopsis-like fungi diseases were studied in vineyards in nine provinces across China. Multi-gene (ITS, ß-tubulin and tef1) analysis coupled with morphology showed that a Neopestalotiopsis sp. and Pestalotiopsis trachicarpicola are associated in causing grapevine fruit rot and trunk diseases in China. Pestalotiopsis trachicarpicola is reported as the causative agent of grapevine diseases in the world for the first time. Neopestalotiopsis sp. caused significantly longer lesions than the other taxon present. This study represents the first attempt to identify and characterize the Pestalotiopsis-like fungi causing grapevine diseases in China using both morphological and molecular approaches.

Inheritance of grain polyphenol oxidase (PPO) activity in multiple wheat (Triticum aestivum L.) genetic backgrounds.

Grain polyphenol oxidase (PPO) activity can cause discoloration of wheat (Triticum aestivum L.) food products. Five crosses (PI 117635/Antelope; Fielder/NW03681; Fielder/Antelope; NW07OR1070/Antelope; NW07OR1066/OR2050272H) were selected to study the genetic inheritance of PPO activity. STS markers, PPO18, PPO29 and STS01, were used to identify lines with putative alleles at the Ppo-A1 and Ppo-D1 loci conditioning low or high PPO activity. ANOVA showed significant genotypic effects on PPO activity (P < 0.0001) in all populations. The generations and generation × genotype effects were not significant in any population. A putative third (null) genotype at Ppo-A1 (no PCR fragments for PPO18) was discovered in NW07OR1066 and NW07OR1070 derived populations, and these had the lowest mean PPO activities. Results demonstrated that both Ppo-A1 and Ppo-D1 loci affect the kernel PPO activity, but the Ppo-A1 has the major effect. In three populations, contrary results were observed to those predicted from previous work with Ppo-D1 alleles, suggesting the markers for Ppo-D1 allele might give erroneous results in some genetic backgrounds or lineages. Results suggest that selection for low or null alleles only at Ppo-A1 might allow development of low PPO wheat cultivars.