RNAi-mediated suppression of the abscisic acid catabolism gene Os ABA8ox1 increases abscisic acid content and tolerance to saline–alkaline stress in rice(Oryza sativa L.)

Saline–alkaline(SA) stress is characterized by high salinity and high alkalinity(high p H), which severely inhibit plant growth and cause huge losses in crop yields worldwide. Here we show that a moderate elevation of endogenous abscisic acid(ABA) levels by RNAi-mediated suppression of Os ABA8 ox1(Os ABA8 ox1-kd), a key ABA catabolic gene, significantly increased tolerance to SA stress in rice plants. We produced Os ABA8 ox1-kd lines in two different japonica cultivars, Dongdao 4 and Nipponbare. Compared with nontransgenic control plants(WT), the Os ABA8 ox1-kd seedlings accumulated 25.9%–55.7% higher levels of endogenous ABA and exhibited reduced plasmalemma injury, ROS accumulation and Na;/K;ratio, and higher survival rates, under hydroponic alkaline conditions simulated by 10, 15, and 20 mmol L-1 of Na;CO;. In pot trials using SA field soils of different alkali levels(p H 7.59, 8.86, and 9.29), Os ABA8 ox1–kd plants showed markedly higher seedling survival rates and more vigorous plant growth, resulting in significantly higher yield components including panicle number(85.7%–128.6%), spikelets per panicle(36.9%–61.9%), branches(153.9%–236.7%), 1000–kernel weight(20.0%–28.6%), and percentage of filled spikelets(96.6%–1340.8%) at harvest time. Under severe SA soil conditions(p H = 9.29, EC = 834.4 μS cm-1),Os ABA8 ox1-kd lines showed an 194.5%–1090.8% increase in grain yield per plant relative to WT plants.These results suggest that suppression of Os ABA8 ox1 to increase endogenous ABA levels provides a new molecular approach for improving rice yield in SA paddies.

An efficient corrosion inhibitor of cassava starch graft copolymer for aluminum in phosphoric acid

Starch is one of the richest natural polymers with low-cost,non-toxic and biodegradable,but is seldom directly used as corrosion inhibitor due to its poor inhibitive ability and low water solubility.To solve this problem,cassava starch-acryl amide graft copolymer(CS-AAGC)was prepared through grafting acryl amide(AA)with cassava starch(CS),and it was firstly examined as an efficient inhibitor for 1060 aluminum in 1.0 mol·L^(-1)H_(3)PO_(4) media.The adsorption behavior of CS-AAGC and its electrochemical mechanism were investigated by weight loss and electrochemical methods.Additionally,the inhibited aluminum surface was fully characterized by a series of SEM,AFM,contact angle measurements and XPS.Results confirm that CS-AAGC performs better inhibitive ability than CS,AA or CS/AA mixture,and the maximum inhibition efficiency of 1.0 g·L^(-1)CS-AAGC is 90.6%at 20℃.CS-AAGC acts as a mixed-type inhibitor while mainly retards the anodic reaction.EIS has three time constants,and the polarization resistance is significantly increased in the presence of CS-AAGC.The micrograph of inhibited aluminum surface is of hydrophobic nature with low surface roughness and little corrosion degree.

High efficient removal of HCN over porous CuO/CeO2 micro-nano spheres at lower temperature range

The porous CeO2 flowerlike micro-nano spheres based materials were prepared to remove HCN effectively at lower temperature range.The CeO2 and a serious of porous flowerlike ceria based materials loaded with metal species including Cu,Ag,Ni,Co and Fe were synthesized by hydrothermal method and precipitation method respectively.The physicochemical properties were probed by means of XRD,H2-TPR,BET,SEM and XPS.The removal ability for 130 mg·m﹣3 HCN over CuO/CeO2 showed the highest activity,the breakthrough time of which was more than 70 min at the condition of 30℃,120,000 h-1 and b 5%(volume)H2O,owe to a higher relative atomic ratio of oxygen vacancies and Oβ,the stronger interaction between metal particle and support,the optimum redox properties.The reaction mechanism was speculated by detecting the reaction products selectivity at different reaction temperature.It was shown that the reaction system for removal of HCN over CuO/CeO2 catalytic material involved chemisorption,catalytic hydrolysis,catalytic oxidation as well as NH3-SCR reactions.

OsbZIP09,a Unique OsbZIP Transcription Factor of Rice,Promotes Rather Than Suppresses Seed Germination by Attenuating Abscisic Acid Pathway

We successfully identified a novel and unique OsbZIP transcription factor,OsbZIP09,whose mutants exhibited longer seeds and less severe pre-harvest sprouting than the wild type,but shared similar germination rate as the wild type under normal germination conditions.The expression of OsbZIP09 was induced by abscisic acid(ABA)and declined as the germination process.As a nucleus-localized transcription factor,the conserved binding motif of OsbZIP09 was identified via DNA affinity purification sequencing technique.Further evidences indicated that OsbZIP09 directly enhanced the expression of ABA catabolism gene ABA8ox1,thus reducing ABA accumulation.In addition,OsbZIP09 also directly bound to the promoter of LEA3 gene to inhibit its expression,thus further alleviating the suppressive effect of ABA on seed germination.These results demonstrated that OsbZIP09 likely functions as a brake of the ABA pathway to attenuate the inhibitory effect of ABA on rice seed germination via dual strategies.