Gossypium hirsutum races are believed to be potential reservoirs of desirable traits, which can play crucial roles to overcome the existing narrow genetic base of modern Upland cotton cultivars.  However, prior to utilizing the races in cotton improvement programs, understanding their genetic constitutions is needed.  Thus, this study used molecular and morphological techniques to characterize 110 G. hirsutum germplasm including 109 semi-wild accessions and one Upland cotton cultivar, CRI12.  In the study, 104 SSR markers detected 795 alleles, with an average of 7.64 alleles per marker, ranging from 3 to 14, and average polymorphism information content (PIC) value of 0.71.  And 96 of the markers were found to be highly informative, with PIC value≥0.50.  Pairwise genetic similarity coefficient across the accessions ranged from 0.19 to 1.00, with an average value of 0.46.  Morphological characterization was done using fiber length, fiber strength, micronaire, fiber uniformity index, and fiber elongation.  Pairwise taxonomic distance within the accessions ranged from 0.17 to 3.41, with a mean of 1.33.  The SSR and fiber quality traits data set based unweighted pair group method of arithmetic mean (UPGMA) analysis grouped the accessions into 7 and 12 distinct clusters, respectively, that corresponds well with the results of principal component analysis (PCA).  Our study revealed the existence of vast molecular and morphological diversities within the accessions and provided valuable information on each semi-wild accession for quick and better informed germplasm utilization in cotton breeding programs.   

We carried out a pool culture experiment to determine the optimal water treatment depth in loam and clay soils during the late growth stage of super rice.  Three controlled water depth treatments of 0–5, 0–10 and 0–15 cm below the soil surface were established using alternate wetting and drying irrigation, and the soil water potential (0 to –25 kPa) was measured at 5, 10 and 15 cm.  A 2-cm water layer was used as the control.  We measured soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and rice yield.  The results showed that the 0–5-cm water depth treatment significantly increased root antioxidant enzyme activities in loam soil compared with the control, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield did not differ from those of the control.  The 0–10- and 0–15-cm water depth treatments also increased root antioxidant enzyme activities, whereas soil enzyme activities, chlorophyll fluorescence parameters and yield decreased.  In clay soil, the soil enzyme activities, root antioxidant enzyme activities, chlorophyll fluorescence parameters, and yield did not change with the 0–5-cm water treatment, whereas the 0–10- and 0–15-cm water treatments improved these parameters.  Therefore, the appropriate depths for soil water during the late growth period of rice with a 0 to –25 kPa water potential were 5 cm in loam and 15 cm in clay soil.

Accurate assessment of soil loss caused by rainfall is essential for natural and agricultural resources management.  Soil erosion directly affects the environment and human sustainability.  In this work, the empirical and contemporary model of revised universal soil loss equation (RUSLE) was applied for simulating the soil erosion rate in a karst catchment using remote sensing data and geographical information systems.  A scheme of alterative sub-models was adopted to calculate the rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover management (C) and conservation practice (P) factors in the geographic information system (GIS) environment.  A map showing the potential of soil erosion rate was produced by the RUSLE and it indicated the severe soil erosion in the study area.  Six classes of erosion rate are distinguished from the map: 1) minimal, 2) low, 3) medium, 4) high, 5) very high, and 6) extremely high.  The RUSLE gave a mean annual erosion rate of 30.24 Mg ha^–1 yr^–1 from the 1980s to 2000s.  The mean annual erosion rate obtained using RUSLE is consistent with the result of previous research based on in situ measurement from 1980 to 2009.  The high performance of the RUSLE model indicates the reliability of the sub-models and possibility of applying the RUSLE on quantitative estimation.  The result of the RUSLE model is sensitive to the slope steepness, slope length, vegetation factors and digital elevation model (DEM) resolution.  The study suggests that attention should be given to the topographic factors and DEM resolution when applying the RUSLE on quantitative estimation of soil loss.

Phosphomannose isomerase (PMI) encoding gene manA is a desirable selective marker in transgenic research. Understanding of its expression patterns in transgenic plant and establishing highly sensitive detection method based on immunoassay have great impacts on the application of PMI. In this study, PMI-specific monoclonal antibodies were generated using recombinant protein as immunogen, and could be used in Western blot to detect as little as 0.5 ng His-tagged PMI protein or rice expressed PMI protein in sample accounted for 0.4% of single rice grain (about 0.08 mg). PMI protein driven by CaMV-35S promoter was detected in dozens of tested tissues, including root, stem, leaf, panicle, and seed at all developmental stages during rice growing, and PMI protein accounted for about 0.036% of total protein in the leaves at seedling stage. The established method potentially can be used to monitor PMI protein in rice grains.

    Plant WRKY transcription factors are involved in various physiological processes, including biotic and abiotic stress responses, as well as developmental processes. In this study, the expression patterns of the WRKY68 protein during interactions between rice 4021 containing the bacterial blight resistance gene Xa21 and Xanthomonas oryzae pv. oryzae (Xoo) were investigated. A possible modified form of the WRKY68 protein appeared in the Xa21-mediated disease resistance response, and its expression levels were similar in compatible and incompatible responses, but differed significantly from that of the mock control treatment, suggesting that WRKY68 may be involved in the bacterial blight response in rice. To further understand WRKY68’s roles in the resistance signaling pathway, WRKY68 recombinant protein was expressed in Escherichia coli and a microscale thermophoresis analysis was performed to investigate the interactions between WRKY68 and cis-elements in crucial pathogenesis-related (PR) genes. The results showed that the WRKY68 protein binds to W-boxes in the PR1b promoter region, with an apparent dissociation constant of 25 nmol L^–1, while the binding between WRKY68 and PR10a was W-box independent. The results suggested that a possible modified form of the WRKY68 protein was induced during the interaction between rice and Xoo, which then regulated the activity of the downstream PR genes by binding with the W-boxes in the PR1b gene’s promoter region. Moreover, the constitutive transcription of the WRKY68 gene in dozens of rice tissues and the expression of the WRKY68 protein in leaves during all growth stages suggests that WRKY68 plays important roles in rice during normal growth processes.