Stenderlange2348

Trema tomentosa (Roxb.) Hara belonging to Ulmaceae displayed abnormal symptoms including witches'-broom, internode shortening, leaf chlorosis and leaflet that affected seriously their growth causing financial loss and ecological damage in China. During August through September 2020, these plants with the symptoms were first found and collected in Dingan and Qinghai counties of Hainan province, China. PCR were performed using the primers R16mF2/R16mR1 and secAfor1/secArev3 specific for phytoplasma 16S rRNA and secA gene fragments. The two gene fragments of the DNA extracted from the four disease samples were identical, with length of 1303 bp 16S rRNA and 587 bp secA gene fragments. The phytoplasma strain was named as Trema tomentosa witches'-broom (TtWB) phytoplasma, TtWB-hn strain. Phylogenetic and computer-simulated RFLP analyses based on the nearly full-length 16S rRNA gene sequence indicated that the TtWB phytoplasma strain is more closely related to the 16SrXXXII-A subgroup than to the other subgroups within 16SrXXXII group. It may represent a new subgroup, designed as 16SrXXXII-D subgroup, which is distinct from the other phytoplasma subgroups within the 16SrXXXII group. To our knowledge, this is the first report showing the occurrence of the phytoplasma strain belongs to 16SrXXXII-D subgroup associated with witches'-broom disease in Trema tomentosa in China. Genetic analysis indicated that the TtWB strain was closely related to the phytoplasma strains infecting periwinkle, oil palm, coconut palm in Malyasian, Camptotheca acuminate in Yunnan province of China and Elaeocarpus zollingeri in Japan.Black shank is a devastating disease of tobacco caused by Phytophthora nicotianae. Host resistance has been an integral part of black shank management, but after the loss of Php single-gene resistance following its widespread deployment in the 1990s, growers have relied on varieties with varying levels of partial resistance. Partial resistance is effective in suppressing disease, but continued exposure can result in an increase in pathogen aggressiveness that threatens durability of the resistance to P. nicotianae. Aggressiveness components in P. nicotianae were characterized following adaptation on two sources of partial resistance, Fla 301 and the Wz gene from Nicotiana rustica. An aggressive isolate of the two major races of P. nicotianae, race 0 and race 1, were adapted for either 'one/two' or 'five/six' generations on the two resistance sources, giving four sets of isolates based on race, number of generations of adaptation, and source of resistance. Across the four sets of isolates, adapted isolates infected higher proportions of root tips, produced more sporangia per infected root tip, and caused larger lesions than their respective non-adapted isolates of the same race and from the same resistance source. Adapted isolates also produced more aggressive zoospore progeny than the non-adapted isolates. Adaptation to partial resistance involves multiple aggressiveness components that results in the increased aggressiveness observed for P. nicotianae. These results improve our knowledge on the nature of P. nicotianae adaptation to partial resistance in tobacco and indicate that different resistance sources are likely to select for similar aggressiveness components in the pathogen.Random-effect meta-analyses were performed on data from 240 field trials conducted between 2005 and 2018 across nine U.S. selleck chemicals states and Ontario, Canada, to quantify the yield response of soybean after application of foliar fungicides at beginning pod (R3) stage. Meta-analysis showed that the overall mean yield response when fungicide was used compared with not applying a fungicide was 2.7% (110 kg/ha). Moderator variables were also investigated and included fungicide group, growing season, planting date, and base yield, which all significantly influenced the yield response. There was also evidence that precipitation from the time of planting to the R3 growth stage influenced yield when fungicide was used (P = 0.059). Fungicides containing a premix of active ingredients from multiple groups (either two or three ingredients) increased the yield by 3.0% over not applying a fungicide. The highest and lowest yield responses were observed in 2005 and 2007, respectively. Better yield response to fungicides (a 3.0% increase) occurred when soybean crops were planted not later than 21 May and when total precipitation between planting and the R3 application date was above historic averages. Temperatures during the season did not influence the yield response. Yield response to fungicide was higher (a 4.7% increase) in average yield category (no spray control yield 2,878 to 3,758 kg/ha) and then gradually decreased with increasing base yield. Partial economic analyses indicated that use of foliar fungicides is less likely to be profitable when foliar diseases are absent or at low levels.Trichoderma gamsii T6085 has been investigated for many years as a beneficial isolate for use in the biocontrol of Fusarium head blight (FHB) of wheat caused primarily by Fusarium graminearum. Previous work focused on application of T6085 to wheat spikes at anthesis, whereas application to soil before and/or at sowing has received limited attention. In the present study, the competitive ability of T6085 on plant residues against F. graminearum was investigated. Results showed a significant reduction of wheat straw colonization by the pathogen and of the development of perithecia, not only when T6085 was applied alone but also in the presence of a Fusarium oxysporum isolate (7121), well known as a natural competitor on wheat plant residues. T6085 was able to endophytically colonize wheat roots, resulting in internal colonization of the radical cortex area, without reaching the vascular system, as confirmed by confocal microscopy. This intimate interaction with the plant resulted in a significant increase of the expression of the plant defense-related genes PAL1 and PR1. Taken together, competitive ability, endophytic behavior, and host resistance induction represent three important traits that can be of great use in the application of T6085 against FHB, not only on spikes at anthesis but potentially also in soil before and/or at sowing.