The roots of Salvia yunnanensis, an herbaceous perennial widely distributed in Southwest China, is often used as a substitute for S. miltiorrhiza, a highly valued plant in traditional Chinese medicine (Wu et al. 2014). In June 2023, wilted plants of S. yunnanensis were observed in Wenshan City (23.20°N, 104.01°E), China. The average disease incidence was 40% to 65% and the total area affected by the disease was approximately 50 ha. The infected plants displayed wilted leaves, black necrotic lesions on roots, and eventually plant death. Fungal colonies with similar morphology were consistently isolated from the symptomatic roots. Eighteen monosporic isolates were individually cultured on potato dextrose agar (PDA) in separate petri dishes at 25 ± 1°C in darkness. After 7 days, the mycelia within the colonies exhibited a cottony texture and the colors ranged from white to pink or purple, while their reverse sides were white to purple. After 20 days incubation on carnation leaf agar (CLA) medium, spore characteristics of the isolates were evaluated (Zheng et al. 2024). On CLA medium, macroconidia had 2 to 5 septa, usually 3 septa, measuring 21.7 to 39.8 × 4.0 to 6.5 μm (n = 100). Microconidia were falciform, slightly curved or straight, measuring 6.8 to 15.4 × 2.5 to 5.4 μm (n = 100), with 0 to 1 septa. Chlamydospores were globose to subglobose, intercalary or terminal, with an average diameter of 8.9 μm (n = 100). Morphologically, the isolates were identified as Fusarium oxysporum (Lombard et al. 2019; Zheng et al. 2024). To confirm the identification, the translation elongation factor 1-α (EF1α) region was amplified with the primers EF-1/EF-2 (O'Donnell et al. 1998) and the RNA polymerase second largest subunit region (RPB2) was amplified with the primers fRPB2-6f/fRPB2-7cr (Eddouzi et al. 2013). The EF1α (GenBank accession no. PP805676) and RPB2 (PQ383276) sequences of isolate DS10-1 were compared with all sequences in the FUSARIUM ID database (O'Donnell et al. 2022) using polyphasic identification. The highest similarity (100%) was with F. oxysporum isolates, including the ex-epitype of Fusarium cugennagense isolate InaCC F984 (100% similarity). To further assess the phylogenetic relationships, a phylogenetic tree was constructed based on the Neighbor-Joining method in MEGA-X (Kumar et al. 2018). The tree confirmed that the isolate DS10-1 was closely related to F. oxysporum. Pathogenicity tests of the 18 isolates were conducted on five healthy one-year-old S. yunnanensis plants per isolate. Inoculum (1 ml of 106 conidia/ml) of each strain was brushed onto the roots of individual plants with a paintbrush. As controls, five plants were inoculated with sterile water. All plants were potted in plastic containers (diameter = 25 cm, five plants per pot) filled with a sterilized substrate mixture of sand and vermiculite (1:1, v/v), and maintained in the greenhouse at 20 to 26°C with 80% relative humidity. After 45 days, symptoms similar to those observed in the field were present on the roots of all plants inoculated with the 18 isolates, whereas the controls remained symptomless. The experiment was repeated two times with similar results. The same pathogens were consistently reisolated from inoculated roots and confirmed as F. oxysporum based on morphological and molecular analyses. F. oxysporum has been previously reported to cause root disease in various hosts, and to our knowledge, this is the first report of F. oxysporum causing root rot on S. yunnanensis in China. Therefore, subsequent crops should be grown to circumvent this disease.
The glutamate decarboxylase (GAD) system of Lactobacillus brevis involves two isoforms of GAD, GadA and GadB, which catalyze the conversion of L-glutamate to γ-aminobutyric acid (GABA) in a proton-consuming reaction contributing to intracellular pH homeostasis. However, direct experimental evidence for detailed contributions of gad genes to acid tolerance and GABA production is lacking.Molecular analysis revealed that gadB is cotranscribed in tandem with upstream gadC, and that expression of gadCB is greatly upregulated in response to low ambient pH when cells enter the late exponential growth phase. In contrast, gadA is located away from the other gad genes, and its expression was consistently lower and not induced by mild acid treatment. Analysis of deletion mutations in the gad genes of L. brevis demonstrated a decrease in the level of GAD activity and a concomitant decrease in acid resistance in the order of wild-type> ΔgadA> ΔgadB> ΔgadC> ΔgadAB, indicating that the GAD activity mainly endowed by GadB rather than GadA is an indispensable step in the GadCB mediated acid resistance of this organism. Moreover, engineered strains with higher GAD activities were constructed by overexpressing key GAD system genes. With the proposed two-stage pH and temperature control fed-batch fermentation strategy, GABA production by the engineered strain L. brevis 9530: pNZ8148-gadBC continuously increased reaching a high level of 104.38 ± 3.47 g/L at 72 h.This is the first report of the detailed contribution of gad genes to acid tolerance and GABA production in L. brevis. Enhanced production of GABA by engineered L. brevis was achieved, and the resulting GABA level was one of the highest among lactic acid bacterial species grown in batch or fed-batch culture.
Lakes in arid regions of Central Asia act as essential components of regional water cycles, providing sparse but valuable water resource for the fragile ecological environments and human lives. Lakes in Central Asia are sensitive to climate change and human activities, and great changes have been found since 1960s. Mapping and monitoring these inland lakes would improve our understanding of mechanism of lake dynamics and climatic impacts. ICESat/GLAS satellite laser altimetry provides an efficient tool of continuously measuring lake levels in these poorly surveyed remote areas. An automated mapping scheme of lake level changes is developed based on GLAS altimetry products, and the spatial and temporal characteristics of 9 typical lakes in Central Asia are analyzed to validate the level accuracies. The results show that ICESat/GLAS has a good performance of lake level monitoring, whose patterns of level changes are the same as those of field observation, and the max differences between GLAS and field data is 3cm. Based on the results, it is obvious that alpine lakes are increasing greatly in lake levels during 2003-2009 due to climate change, while open lakes with dams and plain endorheic lakes decrease dramatically in water levels due to human activities, which reveals the overexploitation of water resource in Central Asia.
【Objective】To grope the optimizing cultivation patterns of rice genetic diversity and the effects of rice population structure for rice blast control.【Method】Two rice varieties different of genetic backgrounds --a hybrid and a glutinous rice variety were chosen to study the efficacy of optimizing cultivation patterns for mixture planting blast control. 【Result】After two years of plot experiments, the results showed that different population structure of mixture planting had different rice blast controll efficacy for Huangkenuo. The controll efficacy increased with the increasing of the ratio of hybrid variety in the mixture. When the population structure was 1﹕15.01 the controll efficacy of leaf blast reached 100% and that of panicle blast reached to 100% at the ratio of 1﹕12.40. The compound yields of all the mixture plots were more than that of monoculture, and land equivalent ratio (LER) of mixture plots was more than 1. 【Conclusion】The optimizing population structure ratio was 1﹕12.40-18.88, not only because they had better efficacy for rice blast control, but also they had higher yields and better economic benefits.
Two alkane hydroxylase-rubredoxin fusion gene homologs (alkW1 and alkW2) were cloned from a Dietzia strain, designated DQ12-45-1b, which can grow on crude oil and n-alkanes ranging in length from 6 to 40 carbon atoms as sole carbon sources. Both AlkW1 and AlkW2 have an integral-membrane alkane monooxygenase (AlkB) conserved domain and a rubredoxin (Rd) conserved domain which are fused together. Phylogenetic analysis showed that these two AlkB-fused Rd domains formed a novel third cluster with all the Rds from the alkane hydroxylase-rubredoxin fusion gene clusters in Gram-positive bacteria and that this third cluster was distant from the known AlkG1- and AlkG2-type Rds. Expression of the alkW1 gene in DQ12-45-1b was induced when cells were grown on C(8) to C(32) n-alkanes as sole carbon sources, but expression of the alkW2 gene was not detected. Functional heterologous expression in an alkB deletion mutant of Pseudomonas fluorescens KOB2Δ1 suggested the alkW1 could restore the growth of KOB2Δ1 on C(14) and C(16) n-alkanes and induce faster growth on C(18) to C(32) n-alkanes than alkW1ΔRd, the Rd domain deletion mutant gene of alkW1, which also caused faster growth than KOB2Δ1 itself. In addition, the artificial fusion of AlkB from the Gram-negative P. fluorescens CHA0 and the Rds from both Gram-negative P. fluorescens CHA0 and Gram-positive Dietzia sp. DQ12-45-1b significantly increased the degradation of C(32) alkane compared to that seen with AlkB itself. In conclusion, the alkW1 gene cloned from Dietzia species encoded an alkane hydroxylase which increased growth on and degradation of n-alkanes up to C(32) in length, with its fused rubredoxin domain being necessary to maintain the functions. In addition, the fusion of alkane hydroxylase and rubredoxin genes from both Gram-positive and -negative bacteria can increase the degradation of long-chain n-alkanes (such as C(32)) in the Gram-negative bacterium.
Four upland cotton ( Gossypium hirsutum L.) lines, NC18‐07 (Reg. no. GP‐1052, PI 690767), NC18‐08 (Reg. no. GP‐1053, PI 690768), NC18‐09 (Reg. no. GP‐1054, PI 690769), and NC18‐10 (Reg. no. GP‐1055, PI 690770), were developed by the Department of Crop and Soil Sciences at North Carolina State University. The four upland cotton lines have improved yield production and some good fiber quality traits. All four lines were derived from a random mated population using multiple parental lines. These four lines were compared with commercial check cultivars ‘DP393’, ‘Sure‐Grow 747’, and ‘UA48’ over 2 yr in Clayton, NC. NC18‐07 produced 7.6 to 34.2% greater lint yields than that of the checks and had 15.2% greater elongation value than that of UA48. NC18‐08 produced 5.9 to 32.1% greater lint yield than the checks. NC18‐09 yielded 2.2 to 27.5% greater lint than checks and showed 44.7 and 22.3% greater elongation values than that of UA48 and parental lines, respectively. Germplasm line NC18‐10 produced 1.0 to 26.0% greater lint yield than the commercial checks and also displayed 26.5 and 7.0% greater elongation values than that of UA48 and parental lines, respectively. These lines could be valuable sources for cotton breeding and programs focusing on improving yield as well as fiber elongation.
Abstract In the United States of America, delimitation trapping surveys with square grids have been used for decades for exotic insects without rigorous evaluation. We used simulations to investigate the effectiveness of two representative designs: an 8-km grid for Acrolepiopsis assectella (leek moth) and a 14.5-km grid for Ceratitis capitata (Mediterranean fruit fly, “Medfly”). We investigated grid compositions and design factors, measuring performance as the mean probability of pest capture over all traps, p (capture), and designed improved grids for both species. For the standard designs, p (capture) was 0.86 for leek moth and 0.71 for Medfly, with the latter performing better due to greater lure and trap attractiveness. For both designs, 86 percent or more of mean p (capture) came from core area captures. Egress testing indicated that both grids were oversized. An improved grid for leek moths would use 177 traps in a 4.8-km diameter circle, which had mean p (capture) = 0.73 and reduced the cost by 80 percent. The best Medfly grid was a 4.8-km diameter circle with 232 traps, which gave mean p (capture) of 0.66 and reduced the cost by 86 percent. Simulation may be used to improve trapping survey plans, often saving significantly on costs while maintaining survey performance.
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