二氢卟吩铁对花针期干旱及复水后花生叶片光合特性的影响

为阐明新型植物生长调节剂二氢卟吩铁(ICe6)影响花针期干旱及复水后花生光合特性的生理机制,于2021和2022年在江苏省农业科学院防雨旱棚内进行盆栽试验,研究干旱及复水后ICe6对花生光合特性及干物质积累与分配的影响。结果表明:干旱结束时,干旱胁迫显著降低了花生叶片的光合参数和RuBPCase活性,光合基因AhRuBP相对表达量下调、AhPORA上调,喷施ICe6显著提高干旱植株叶片的净光合速率(P_(n))和蒸腾速率(T_(r)),叶片AhPORA和AhLHCB3的基因相对表达量亦显著上调,叶片干物质分配比例增加,胁迫指数WSI降低。复水后第7天,干旱胁迫植株的光合参数迅速恢复,喷施ICe6的干旱植株的Tr、RuBPCase活性显著大于喷施清水植株,Tr两年增幅为11.7%和20.8%,RuBPCase活性增幅达14.9%和69.9%;AhRuBP基因相对表达量亦显著上调。复水后第20天,喷施ICe6的干旱植株叶绿素a(Chl a)含量、P_(n)、气孔导度(G_(s))、Tr、RuBPCase活性仍显著高于喷施清水处理;喷施ICe6亦显著提升植株的生殖生长,荚果干物质量增加26.7%,荚果干物质分配比例增大15.6%。综上所述,ICe6可以显著提升干旱胁迫下花生叶片的光合性能,并促进复水后花生光合性能的快速恢复。

野猪源猪圆环病毒4型的发现及其Cap基因序列分析

猪圆环病毒4型(PCV4)于2019年在我国家猪中首次检测到,并发现其可能与多系统呼吸道疾病、腹泻及皮炎肾病综合征疾病有关。为了解该病毒在野猪中的流行和遗传进化特征,本研究采集江西省山区野猪组织样品25份,包含淋巴结、肾脏、脾脏,采用探针法荧光定量PCR(Taq Man qPCR)对组织样品检测,对PCV4阳性组织样品采用普通PCR扩增其Cap基因并分析其同源性及遗传进化关系。结果显示,25份样品中检测到3份PCV4阳性样品,检出率为12%(3/25);普通PCR扩增结果显示,在3份阳性样品中均扩增到约1300 bp的目的条带,测序后的序列比对分析结果显示其均为PCV4全长Cap基因序列(JXNC-2020、JXYC-2020及JXGZ-2020)。Cap基因的同源性分析显示,3个野猪源PCV4 Cap基因序列间的同源性为98.69%~100%,氨基酸序列间的同源性为97.1%~100%;与韩国野猪源PCV4流行株E115 Cap基因序列的同源性为98.11%~98.54%,氨基酸序列的同源性为96.93%~98.25%;与国内家猪源PCV4 Cap基因序列的同源性为98.54%~99.13%,氨基酸序列同源性97.37%~99.12%;与E115株相比,本研究获得的3个PCV4 Cap蛋白氨基酸序列分别存在3个及7个突变氨基酸。与国内PCV4相比,PCV4 Cap基因JXGZ-2020编码的氨基酸序列突变数明显少于其与韩国流行株相比。Cap基因的系统发育分析显示,野猪源PCV4与家猪源PCV4同属于一个分支,与圆环病毒属其他病毒处于不同分支。上述结果表明,野猪源PCV4与家猪源PCV4的亲缘关系较近,间接表明野猪可以促进PCV4的扩散与传播。本研究结果首次拓展了PCV4的宿主范围,为进一步研究PCV4的流行及基因组特征提供参考。

氯化胆碱浸种对盐迫下稻种萌发及幼苗生长的影响

为了明确氯化胆碱对NaCl胁迫的缓解作用,以水稻品种隆粳20和粳2837为材料,采用0、200、400、600和800 mg/L浓度的氯化胆碱溶液浸种处理研究氯化胆碱浸种对NaCl胁迫下水稻种子萌发以及幼苗生长的影响。结果表明:盐胁迫下水稻种子的发芽势、发芽率等均显著降低,而根长、芽长等指标随着盐浓度的升高受到不同程度的抑制,试验表明7.5 g/L NaCl抑制率约为50%,因此选取7.5 g/L NaCl溶液作为对不同浓度氯化胆碱浸种后的水稻种子萌发和幼苗胁迫处理的盐浓度。氯化胆碱浸种能明显提高NaCl胁迫下水稻种子的发芽势、发芽率,同时增加根长、芽长等指标,对NaCl胁迫下水稻种子萌发以及幼苗的生长具有明显的缓释作用。由此说明,氯化胆碱浸种可以缓解NaCl胁迫对水稻种子萌发的影响,提高水稻种子的耐盐性。

47%异隆·丙·氯吡可湿性粉剂对沭阳县水稻田杂草防效及安全性评价

为筛选施用适期宽、适应性广、安全高效的除草剂新品种,通过大田示范验证47%异隆·丙·氯吡可湿性粉剂在江苏省沭阳县水稻旱直播田、机插秧田、手插秧田适期适量施用对杂草的防效及对水稻的安全性。结果表明,47%异隆·丙·氯吡可湿性粉剂在旱直播水稻播后苗前或立针期以2 100 g/hm^2喷雾处理、在机插秧水稻移栽3 d前以1 050 g/hm^2粗喷雾法处理结合移栽7 d后以1 050 g/hm^2毒肥法处理、在手插秧水稻移栽6 d后以1 050 g/hm^2毒土法处理对江苏省沭阳县稻田稗属杂草、马唐、千金子、丁香蓼、异型莎草等杂草的株防效和鲜质量防效均高于91%,且对水稻安全。

Cloning and Characterization of a Salt Tolerance-Associated Gene Encoding Trehalose-6-Phosphate Synthase in Sweetpotato

Trehalose plays an important role in metabolic regulation and abiotic stress tolerance in a variety of organisms. In plants, its biosynthesis is catalyzed by two key enzymes： trehalose-6-phosphate synthase（TPS） and trehalose-6-phosphate phosphatase（TPP）. In the present study, a TPS gene, named IbTPS, was first isolated from sweetpotato（Ipomoea batatas（L.） Lam.） cv. Lushu 3 by rapid amplification of cDNA ends（RACE）. The open reading frame（ORF） contained 2 580 nucleotides encoding 859 amino acids with a molecular weight of 97.433 kDa and an isoelectric point（pI） of 5.7. The deduced amino acid sequence showed high identities with TPS of other plants. Real-time quantitative PCR analysis revealed that the expression level of IbTPS gene was significantly higher in stems of Lushu 3 than in its leaves and roots. Subcellular localization analysis in onion epidermal cells indicated that IbTPS gene was located in the nucleus. Transgenic tobacco（cv. Wisconsin 38） plants over-expressing IbTPS gene exhibited significantly higher salt tolerance compared with the control plant. Trehalose and proline content was found to be significantly more accumulated in transgenic tobacco plants than in the wild-type and several stress tolerance related genes were up-regulated. These results suggest that IbTPS gene may enhance salt tolerance of plants by increasing the amount of treahalose and proline and regulating the expression of stress tolerance related genes.

OsMas1,a novel maspardin protein gene,confers tolerance to salt and drought stresses by regulating ABA signaling in rice

Drought and salt stresses,the major environmental abiotic stresses in agriculture worldwide,affect plant growth,crop productivity,and quality.Therefore,developing crops with higher drought and salt tolerance is highly desirable.This study reported the isolation,biological function,and molecular characterization of a novel maspardin gene,OsMas1,from rice.The OsMas1 protein was localized to the cytoplasm.The expression levels of OsMas1 were up-regulated under mannitol,PEG6000,NaCl,and abscisic acid(ABA) treatments in rice.The OsMas1 gene was introduced into the rice cultivar Zhonghua 11(wild type,WT).OsMas1-overexpression(OsMas1-OE) plants exhibited significantly enhanced salt and drought tolerance;in contrast,OsMas1-interference(OsMas1-RNAi) plants exhibited decreased tolerance to salt and drought stresses,compared with WT.OsMas1-OE plants exhibited enhanced hypersensitivity,while OsMas1-RNAi plants showed less sensitivity to exogenous ABA treatment at both germination and post-germination stages.ABA,proline and K+ contents and superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),and photosynthesis activities were significantly increased.In contrast,malonaldehyde(MDA),hydrogen peroxide(H2O2),superoxide anion radical(O2-··),and Na+ contents were significantly decreased in OsMas1-OE plants compared with OsMas1-RNAi and WT plants.Overexpression of OsMas1 up-regulated the genes involved in ABA signaling,proline biosynthesis,reactive oxygen species(ROS)-scavenging system,photosynthesis,and ion transport under salt and drought stresses.Our results indicate that the OsMas1 gene improves salt and drought tolerance in rice,which may serve as a candidate gene for enhancing crop resistance to abiotic stresses.

凹土对甘薯植株生长和生理代谢的影响

通过盆栽试验研究在盐、干旱胁迫下外施凹土对甘薯幼苗生长和生理代谢的影响。在200 mmol/L Na Cl胁迫、干旱胁迫处理下,外施凹土添加到土壤中能够显著增强甘薯的耐盐性和抗旱性;酶活性测定结果显示,外施凹土显著增加盐、干旱胁迫下超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和过氧化酶(POD)的活性;物质含量测定结果显示,在盐、干旱胁迫下外施凹土显著增加甘薯的脯氨酸、相对水、可溶性糖和叶绿素的含量,显著降低丙二醛(MDA)和过氧化氢(H_2O_2)的含量。结果表明,凹土可以缓解盐、干旱胁迫对甘薯造成的伤害,从而增强甘薯植株的耐盐性和抗旱性。

Overexpression of IbMIPS1 gene enhances salt tolerance in transgenic sweetpotato

Myo-inositol-1-phosphate synthase（MIPS） is a key rate limiting enzyme in the de novo biosynthesis of myo-inositol in plants.In the present study,the IbMIPS1 gene was introduced into sweetpotato cultivar Xushu 18 and the transgenic plants exhibited significantly enhanced salt tolerance compared with the wild-type（WT）.Overexpression of IbMIPSI up-regulated the salt stress responsive genes,including myo-inositol monophosphatase（MIPP）,pyrroline-5-carboxylate synthase（P5CS）,pyrroline-5-carboxylate reductase（P5CR）,psbA,phosphoribulokinase（PRK）,and superoxide dismutase（SOD） genes,under salt stress.Inositol and proline content,SOD and photosynthesis activities were significantly increased,whereas malonaldehyde（MDA） and H_2O_2 contents were significantly decreased in the transgenic plants.These findings suggest that the IbMIPS1 gene may enhance salt tolerance of sweetpotato by regulating the expression of salt stress responsive genes,increasing the content of inositol and proline and enhancing the activity of photosynthesis.

干旱胁迫下外源海藻糖对糯玉米幼苗生理特性的影响

以苏玉糯5号为供试材料,研究干旱胁迫条件下外源海藻糖对糯玉米幼苗根系和叶片抗氧化系统及渗透调节物质的影响。结果表明,干旱胁迫显著降低叶片叶绿素含量和根系活力,喷施外源海藻糖后这两类物质含量增加。干旱胁迫下喷施外源海藻糖增加玉米根系和叶片中可溶性蛋白、可溶性糖、抗坏血酸(AsA)、还原型谷胱甘肽(GSH)含量,增强糯玉米幼苗根系和叶片的超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)等活性,降低超氧阴离子产生速率(O2-)、丙二醛(MDA)等含量。外源海藻糖处理下叶片中可溶性糖、可溶性蛋白、AsA和GSH含量增加幅度大于根系,叶片中丙二醛含量降幅大于根系。表明喷施外源海藻糖缓解干旱胁迫对叶片伤害效果大于根系。干旱胁迫下喷施外源海藻糖能够增强糯玉米抗旱能力,减小干旱伤害。