Small auxin up RNA (SAUR) is a large gene family that is widely distributed among land plants.  In this study, a comprehensive analysis of the SAUR family was performed in sweet cherry, and the potential biological functions of PavSAUR55 were identified using the method of genetic transformation.  The sweet cherry genome encodes 86 SAUR members, the majority of which are intron-less.  These genes appear to be divided into seven subfamilies through evolution.  Gene duplication events indicate that fragment duplication and tandem duplication events occurred in the sweet cherry.  Most of the members mainly underwent purification selection pressure during evolution.  During fruit development, the expression levels of PavSAUR16/45/56/63 were up-regulated, and conversely, those of PavSAUR12/61 were down-regulated.  Due to the significantly differential expressions of PavSAUR13/16/55/61 during the fruitlet abscission process, they might be the candidate genes involved in the regulation of physiological fruit abscission in sweet cherry.  Overexpression of PavSAUR55 in Arabidopsis produced earlier reproductive growth, root elongation, and delayed petal abscission.  In addition, this gene did not cause any change in the germination time of seeds and was able to increase the number of lateral roots under abscisic acid (ABA) treatment.  The identified SAURs of sweet cherry play a crucial role in fruitlet abscission and will facilitate future insights into the mechanism underlying the heavy fruitlet abscission that can occur in this fruit crop.

Viral diseases are among the most critical damaging factors that impose a global threat to the cucurbit industry.  China is the world’s leading country for the production and consumption of cucurbits.  Guangdong, a province in southern China dominated by the tropical and subtropical climate, favors the survival of different plant viruses and their vectors.  Five main cucurbit crops showing various disease symptoms were surveyed and collected to identify viruses infecting cucurbits in Guangdong during 2018–2020.  In the field, the incidence ranged from 5–30%, or even 60–100% in the case of severely infected cucurbits.  A total of 357 symptomatic samples were collected and subsequently screened for cucurbit viruses by small RNA deep sequencing and assembly (sRSA).  Seventeen virus species belonging to 10 genera were identified in the five main cucurbit crops.  The most common viruses were papaya ringspot virus (PRSV; Potyvirus), zucchini tigre mosaic virus (ZTMV; Potyvirus), zucchini yellow mosaic virus (ZYMV; Potyvirus), and watermelon silver mottle virus (WSMoV; Orthotospovirus), with infection rates of 24.4, 19.0, 17.1, and 14.3%, respectively.  Notably, the most prevalent viruses were melon yellow spot orthotospovirus (MYSV) in cucumber, PRSV in squash, cucumber green mottle mosaic virus (CGMMV; Tobamovirus) in bottle gourd, WSMoV in white gourd, and ZYMV in luffa.  Mixed infections were prevalent, and the types of mixed infections varied substantially in different cucurbit crops.  Moreover, the full-length nucleotide sequences of watermelon green mottle mosaic virus (WGMMV), CGMMV, and watermelon virus A (WVA; Wamavirus) identified in bottle gourd were cloned and analyzed.  This study is the first reporting WGMMV infecting bottle gourd in China mainland.  In summary, the results demonstrate that in Guangdong, the most prevalent viruses belong to potyviruses, orthotospoviruses, and tobamoviruses groups.  The findings will facilitate agricultural researchers and farmers to plan and implement effective disease control strategies aiming at timely detection and management of cucurbit-infecting viral pathogens.

Ovine bones are the major by-products after slaughtered.  The present study was conducted to extract and characterize acid soluble collagens (ASC) and pepsin soluble collagens (PSC) from ovine bones (Ujumuqin sheep).  Ovine bones collagen were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) as type I collagen.  The results of Fourier transform infrared (FTIR) spectra analysis testified the existence of triple superhelical structure in both ASC and PSC, showing pepsin did not disrupt the triple helical structure of ovine bones collagen.  Glycine, accounting for one-third of total amino acids, was the major amino acid for ovine bones collagen.  Higher imino acid content was responsible for higher thermal denaturation temperature of ovine bones collagen compared to fish collagens.  The isoelectric point of ASC was lower than PSC due to the higher content of acidic amino acids.  Therefore, this study provides the potential reference for collagen extraction and application of ovine bones by-procduct.

This study investigated the influence of activities of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and lactate dehydrogenase-B (LDH-B) on the colour stability of mutton.  From 60 sheep (Bayannur mutton sheep), 15 longissimus dorsi (LD) muscles were selected on the basis of colour stability (R630/580 and a* value) during the storage and classified into three groups (5 for each group) as high colour stability (HCS), intermediate colour stability (ICS) and low colour stability (LCS).  The activities of GAPDH and LDH-B, muscle colour attributes, nicotinamide adenine dinucleuotide (NADH) concentration and lactate concentration were measured.  The samples in HCS had higher activities of GAPDH and LDH-B than the samples in the LCS, and the samples in the HCS group also possessed higher NADH and lower lactate concentration.  The higher activity of dehydrogenase enzyme may result in higher NADH concentrations and colour stability in muscle tissue.  The results suggest that the activity of GAPDH and LDH-B may also play a role in maintaining colour stability.

Rice area has been expanding rapidly during the past 30 years under the influence of global change in northeastern China, which is the northernmost region of rice cultivation in China.  However, the spatio-temporal dynamic changes in rice area are still unclear, although they may have important policy implications for environmental protection and adaptation to climate change.  In this study, we aimed to identify the dynamic changes of the rice area in Heilongjiang Province of northeastern China by extracting data from multiple Landsat images.  The study used ground quadrats selected from Google Earth and the extraction of a confusion matrix to verify the accuracy of extraction.  The overall accuracy of the extracted rice area was higher than 95% as a result of using the artificial neural network (ANN) classification method.  The results showed that the rice area increased by approximately 2.4×10⁶ ha during the past 30 years at an annual rate of 8.0×10⁴ ha, and most of the increase occurred after 2000.  The central latitude of the rice area shifted northwards from 46 to 47°N during the study period, and moved eastwards from 130 to 133°E.  The rice expansion area accounted for 98% of the total change in rice area, and rice loss was notably rare.  The rice expansion was primarily from dryland.  In addition, rice cultivation in marshland and grassland played a minor role in the rice expansion in this region.

A novel phytoplasma was detected in a cherry plum (Prunus cerasifera Ehrh) tree that mainly showed yellow leaf symptom. The tree was growing in an orchard located in Yangling District, Shaanxi Province, China. The leaves started as chlorotic and yellowing along leaf minor veins and leaf tips. Chlorosis rapidly developed to inter-veinal areas with the whole leaf becoming pale yellow in about 1-4 wk. Large numbers of phytoplasma-like bodies (PLBs) were seen under transmission electron microscopy. The majority of the PLBs was spherical or elliptical vesicles, with diameters in range of 0.1-0.6 μm, and distributed in the phloem cells of the infected tissues. A 1246-bp 16S ribosomal RNA (rRNA) gene fragment was amplified from DNA samples extracted from the yellow leaf tissues using two phytoplasma universal primer pairs R16mF2/R16mR1 and R16F2n/R16R2. Phylogenetic analysis using the 16S rRNA gene sequence suggested that the phytoplasma associated with the yellow leaf symptoms belongs to a novel subclade in the aster yellows (AY) group (16SrI group). Virtual and actual restriction fragment length polymorphism (RFLP) analysis of the 16S rRNA gene fragment revealed that the phytoplasma was distinguishable from all existing 19 subgroups in the AY group (16SrI) by four restriction sites, Hinf I, Mse I, Sau3A I and Taq I. The similarity coefficients of comparing the RFLP pattern of the 16S rRNA gene fragment of this phytoplasma to each of the 19 reported subgroups ranged from 0.73 to 0.87, which indicates the phytoplasma associated with the cherry plum yellow leaf (CPYL) symptoms is probably a distinct and novel subgroup lineage in the AY group (16SrI). In addition, the novel phytoplasma was experimentally transmitted to periwinkle (Catharanthus roseus) plants from the tree with CPYL symptoms and then back to a healthy 1-yr-old cherry plum tree via dodder (Cuscuta odorata) connections.

For the scientific management of farmland, it is significant to understand the spatio-temporal variability of soil organic matter and to study the influences of related factors. Using geostatistical theory, GIS spatial analysis, trend analysis and a Geographically Weighted Regression (GWR) model, this study analyzed the response of soil organic matter to climate and socio-economic factors in central Heilongjiang Province during the past 25 years. Second soil survey data of China for 1979-1985, 2005 field sampling data, climate observations and socio-economic data for 1980-2005 were analyzed. First, soil organic matter in 2005 was spatially interpolated using the Co-Kriging method along with auxiliary data sets of soil type and pH. The spatio-temporal variability was then studied by comparison with the 1980s second soil census data. Next, the temporal trends in climate and socio-economic factors over the past 25 years were investigated. Finally, we examined the variation of the response of soil organic matter to climate and socio-economic factors using the GWR model spatially and temporally. The model showed that 53.82% area of the organic matter content remained constant and 29.39% has decreased during the past 25 years. The impact of precipitation on organic matter content is mainly negative, with increasing absolute values of the regression coefficient. The absolute value of regression coefficient of annual average temperature has decreased, and more areas are now under its negative effects. In addition, the areas of positive regression coefficient of annual sunshine hours have northward shifted, with the increasing absolute value of positive coefficient and decreasing absolute value of negative coefficient. The areas of positive regression coefficient of mechanized farming as a socio-economic factor have westward shifted, with the increasing absolute value of negative coefficient and decreasing absolute value of positive coefficient. The area of regions with the positive regression coefficient of irrigation has expanded. The regions with positive regression coefficient of fertilizer use have shrinked. The positive regression coefficient of mulch film consumption has significantly increased. The regression coefficient of pesticide consumption was mainly positive in the west of the study area, while it was negative to the east. Generally, GWR model is capable to investigate the influence of both climatic and socio-economic factors, avoided the insufficiency of other research based on the single perspective of climatic or socio-economic factors. Therefore, we can conclude that GWR model could provide methodological support for global change research and serve as basic reference for cultivated land quality improvement and agricultural decision making.