Effects of Deficit Irrigation on the Photosynthetic and Physiological Characteristics of Leaves and Yield of Isatis tinctoria

以北板蓝根(Isatis tinctoria)为研究对象, 于2018年在河西走廊中部干旱绿洲开展水分控制试验, 设轻、中、重度亏水及充分供水4个控水水平, 通过大田试验探究膜下滴灌条件下亏缺灌溉对板蓝根叶片生理指标、灌水量及产量的影响, 为河西地区板蓝根灌溉策略的制定提供理论依据。结果表明, 板蓝根叶片净光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)因营养和肉质根生长期受到亏缺灌溉影响而显著下降, 降幅随亏水程度的加剧而增大, 轻度亏水处理对叶片光合能力的影响不显著, 且在复水之后存在一定的补偿响应; 轻度亏水处理的产量与对照(8 348.91 kg·hm^-2)相比无显著差异, 而其它处理的产量均有不同程度的下降; 灌水量与产量的拟合关系呈二次抛物线, 即产量不随灌水量的增加而升高。因此, 综合分析表明膜下滴灌调亏降低了板蓝根叶片的光合能力, 而营养生长期轻度亏缺灌溉可以节水并提高产量和灌溉效率。     

β-1,6葡聚糖酶前体编码基因Ss4p对甘蔗黑穗病菌分泌蛋白组的影响

甘蔗(Saccharum spp.)是世界也是中国主要的糖料作物.由甘蔗黑穗病菌(Sporisorium scitamineum)引起的甘蔗黑穗病是中国甘蔗生产上最主要的病害,每年造成重大损失.分泌蛋白在真菌侵染寄主植物与获取营养及病理过程起重要作用.本实验室在分析甘蔗黑穗病菌基因组与转录组数据时,发现1个与真菌细胞壁降解有关的β-1,6葡聚糖酶前体的基因Ssa4p.为了揭示Ssa4p对甘蔗黑穗病菌致病性和分泌蛋白组的影响,本研究利用CRISPR/Cas9和T-DNA双元载体所构建的甘蔗黑穗菌基因敲除系统,成功获得了Ssa4p基因的失活突变株.ΔSsa4p突变株(Δ35-Ssa4p)与野生型菌株JG36的配合能力降低且致病性减弱.用iTRAQ方法对Δ35-Ssa4p和野生型菌株的分泌蛋白组进行比较分析,共鉴定到蛋白质1430个,其中上调差异表达蛋白质685个,下调差异表达蛋白质745个.GO功能富集分析及KEGG分析表明,差异蛋白主要定位于无膜细胞器和核糖体,其功能包括参与核糖体、氨基糖和核苷酸糖代谢等生物学过程.本研究发现β-1,6葡聚糖前体影响植物病原真菌的分泌蛋白,加深了对真菌致病性调控机制的认识.     

Evaluation of the efficacy and safety of hydroxychloroquine in comparison with chloroquine in moderate and severe patients with COVID-19

Science China Life Sciences -     

Using vaginal discharge score (VDS) grading system to evaluate the effect of clinical endometritis on reproductive performance of dairy cows in China

Clinical endometritis (CE) is a major cause in affecting the reproductive performance of dairy cows. The objectives of this study were to ascertain the prevalence of CE and to evaluate the effect of CE on reproductive performance in dairy cows using vaginal discharge score (VDS) grading system. 803 dairy cows were examined by vaginoscope with 4-point VDS at 26 ± 3 days in milk (DIM) and classified into six groups: non-endometritis with VDS 0 (control; CON), endometritis with VDS 1 (MEM), non-treated endometritis with VDS 2 (NTME), treated endometritis with VDS 2 (TME), non-treated endometritis with VDS 3 (NTPE), and treated endometritis with VDS 3 (TPE). Cows in TME and TPE groups were treated with 200 mL of 50% dextrose solution by intrauterine infusion. The prevalence of CE was 33% at 26 ± 3 DIM. Binary logistic regression analysis revealed cows in MEM, NTME and NTPE groups had a less likelihood of first artificial insemination (AI) pregnancy than those in CON group (P < 0.05). Kaplan-Meier survival curves for days open were statistically different (P = 0.004). In Cox regression model, cows in NTME and NTPE groups had a reduced pregnancy rate than those in CON group (P < 0.05). The hazard of pregnancy in NTME group was lower than that in TME group (P = 0.044). Similarly, it was lower for the hazard of pregnancy in NTPE group than in TPE group (P = 0.048). Cows in MEM, NTME, and NTPE groups required more services per pregnancy than those in CON group (P < 0.05). In conclusion, CE examined by the VDS grading system impaired reproductive performance, and mild endometritis with VDS 1 should be treated in the early postpartum period to ameliorate fertility in dairy herds.     

Macrophage migration inhibitory factor regulates joint capsule fibrosis by promoting TGF-β1 production in fibroblasts

Joint capsule fibrosis caused by excessive inflammation results in post-traumatic joint contracture (PTJC). Transforming growth factor (TGF)-β1 plays a key role in PTJC by regulating fibroblast functions, however, cytokine-induced TGF-β1 expression in specific cell types remains poorly characterized. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in inflammation- and fibrosis-associated pathophysiology. In this study, we investigated whether MIF can facilitate TGF-β1 production from fibroblasts and regulate joint capsule fibrosis following PTJC. Our data demonstrated that MIF and TGF-β1 significantly increased in fibroblasts of injured rat posterior joint capsules. Treatment the lesion sites with MIF inhibitor 4-Iodo-6-phenylpyrimidine (4-IPP) reduced TGF-β1 production and relieved joint capsule inflammation and fibrosis. In vitro, MIF facilitated TGF-β1 expression in primary joint capsule fibroblasts by activating mitogen-activated protein kinase (MAPK) (P38, ERK) signaling through coupling with membrane surface receptor CD74, which in turn affected fibroblast functions and promoted MIF production. Our results reveal a novel function of trauma-induced MIF in the occurrence and development of joint capsule fibrosis. Further investigation of the underlying mechanism may provide potential therapeutic targets for PTJC.     

Base editing with high efficiency in allotetraploid oilseed rape by A3A‐PBE system

CRISPR/Cas‐base editing is an emerging technology that could convert a nucleotide to another type at the target site. In this study, A3A‐PBE system consisting of human A3A cytidine deaminase fused with a Cas9 nickase and uracil glycosylase inhibitor was established and developed in allotetraploid Brassica napus. We designed three sgRNAs to target ALS, RGA and IAA7 genes, respectively. Base‐editing efficiency was demonstrated to be more than 20% for all the three target genes. Target sequencing results revealed that the editing window ranged from C1 to C10 of the PAM sequence. Base‐edited plants of ALS conferred high herbicide resistance, while base‐edited plants of RGA or IAA7 exhibited decreased plant height. All the base editing could be genetically inherited from T₀ to T₁ generation. Several Indel mutations were confirmed at the target sites for all the three sgRNAs. Furthermore, though no C to T substitution was detected at the most potential off‐target sites, large‐scale SNP variations were determined through whole‐genome sequencing between some base‐edited and wild‐type plants. These results revealed that A3A‐PBE base‐editing system could effectively convert C to T substitution with high‐editing efficiency and broadened editing window in oilseed rape. Mutants for ALS, IAA7 and RGA genes could be potentially applied to confer herbicide resistance for weed control or with better plant architecture suitable for mechanic harvesting.