OsbZIP01 Affects Plant Growth and Development by Regulating OsSD1 in Rice

As the‘Green Revolution’gene,SD1(encoding GA20ox2),has been widely applied to improve yield in rice breeding.However,research on its transcriptional regulation is limited.Here,we identified a transcription factor OsbZIP01,which can suppress the expression of SD1 and regulate gibberellin(GA)biosynthesis in rice.Knockout mutants of OsbZIP01 exhibited increased plant height,while the overexpression lines showed a semi-dwarf phenotype and diminished germination rate.Furthermore,the semi-dwarf phenotype of OE-bZIP01,was caused by the reduced internode length,which was accompanied by a thin stem width.The predominant expression of OsbZIP01 was observed in leaves and sheaths.OsbZIP01 protein was localized in the nucleus and showed transcriptional repression activity.In addition,OsbZIP01 could directly bind to the promoter of the OsSD1 gene,and inhibit its transcription.The semi-dwarf phenotype of OE-bZIP01 could be rescued by exogenous GA_(3).Meanwhile,the bzip01 sd1 double mutant showed a shorter shoot length compared with the wild type,indicating that OsbZIP01 regulated plant growth mainly through the GA biosynthesis pathway.Collectively,OsbZIP01 negatively regulates GA biosynthesis by restraining SD1 transcription,thereby affecting plant growth and development.

新发展阶段我国农业食物系统转型战略构想研究

进入全面建设社会主义现代化国家的新阶段后,我国农业食物系统正在从“吃得饱”“吃得好”向“吃得营养健康”转变;绿色低碳成为农业食物系统转型的全球共识,包容共享成为农业食物系统转型的中国方案。当前,我国农业食物系统转型面临诸多挑战,以营养过剩和营养缺乏并存、保供和降碳之间存在矛盾、对小农生产者和弱势群体消费者的包容性不足、生产稳定性和供应可控性的韧性能力不强等问题为典型;未来在人口总量下降、城镇化率继续提高的背景下,我国农业食物系统结构有待进一步调整和优化,将加快转向“营养健康‒绿色低碳‒包容共享‒安全韧性”的多赢发展目标。相应主攻方向包括:调整生产体系、丰富食物供给,突出科技创新、优先发展多赢技术,加强政策创设、加大转型投资,优化体制机制、建设高效包容食物链,转变消费理念、引导居民低碳行为。研究建议:启动国家营养相关立法工作,建立国家农业食物系统转型技术储备库,实施国家农业食物系统转型升级科技专项,开展全民营养健康行动。

种子加工、检验理论与技术现状及思考

种子加工及检验是种子向市场流通的关键,是商业化育种中赋予种子商品属性不可或缺的环节。种子加工、检验理论与技术的研究是完善种业产业链、实现规模化商业育种、夯实"育繁推一体化"种业科学的重要一环。中国的种业科学技术体系正在形成与完善之中,受制于行业发展水平,种子加工及检验理论与技术相对薄弱。本文回顾了种子加工及检验理论与技术研究发展历程,提出了完善中国种业科学发展的策略与建议。围绕种业发展的需要,在做好品种优质化繁育的基础上,分析种子加工及检验理论与技术的新方向和新需求,加强种业应用性研究,建立先进的种子质量检验体系,研制适合现代种业发展需求的种子加工设备,打造种子加工产业标准化生产体系,完善种业科学技术学科建设,促进种业产业持续健康发展。

粳稻穗部不同部位籽粒产量相关性状差异及其与内源激素的相关性

【目的】根据灌浆期水稻内源激素水平解析稻穗不同部位籽粒产量性状的差异。【方法】以相同环境下种植的嘉58等6个浙江省常规粳稻品种为实验材料,将稻穗籽粒按一次枝梗在主穗上的节点划分为稻穗上部、中部和下部籽粒,测定了不同部位籽粒水杨酸(SA)、脱落酸(ABA)、吲哚乙酸(IAA)和生物量的动态变化及收获后籽粒千粒重、整精米率、长宽比、胶稠度和碱消值等相关性状。【结果】籽粒在灌浆期内0~35 d处于持续增重状态,且表现为上部>中部>下部,花后35 d各品种不同部位籽粒生物量的变异系数为1.66%~10.26%,35 d以后不同部位籽粒生物量的差距逐渐缩小但仍有差异,籽粒成熟后千粒重仍表现为上部籽粒(25.08~33.88g)>中部(24.04~32.49 g)>下部(23.46~31.78 g);不同部位间籽粒整精米率与长宽比略有差异,且千粒重与长宽比呈极显著正相关(r=0.89, P<0.01),与整精米率呈极显著负相关(r=-0.68, P<0.01);在胶稠度、碱消值方面,品种间的差异显著大于部位间的差异;三种内源激素在不同部位籽粒中的差异均较为显著,且SA差异最为稳定,全周期不同部位间籽粒SA含量变异系数为0.59%~25.90%,ABA和IAA变异系数依次为1.35%~66.25%和0.16%~81.04%。不同部位SA含量在灌浆初期与末期正相反,前期表现为上部籽粒>中部>下部,末期却表现为下部籽粒>中部>上部。【结论】不同部位籽粒的内源激素及产量等相关性状差异均较为显著,激素含量差异以SA最为稳定。SA与ABA和IAA分别呈显著正相关(r=0.54, P <0.05)和极显著正相关(r=0.59, P<0.01),与千粒重呈显著负相关(r=-0.53, P <0.05),其与长宽比和整精米率也分别为极显著负相关(r=-0.66, P <0.01)和极显著正相关(r=0.95, P <0.01)。

矮秆小粒水稻潇湘矮的形态学与分子遗传学分析

【目的】研究揭示潇湘矮矮秆小粒的遗传机制,为潇湘矮的育种利用提供理论基础。【方法】利用水稻育种过程中自然突变而得到的稳定遗传的矮秆小粒水稻材料潇湘矮,对其进行农艺性状考查、赤霉素(GA_3)和油菜素内酯(BR)敏感性分析、遗传学分析,并利用潇湘矮与其近等基因系NIL(NIP)衍生的F_2群体对控制矮秆小粒的基因xxa进行图位克隆,最终利用转基因互补试验验证候选基因。【结果】潇湘矮除表现为矮秆小粒外,其穗长变短,穗型紧凑,千粒重极显著下降。不同浓度梯度的赤霉素(GA_3)和油菜素内酯(BR)处理,发现潇湘矮对GA_3部分敏感,而对BR不敏感。遗传分析发现其符合孟德尔3∶1分离规律。图位克隆将xxa基因定位于第5染色体In Del标记F81和F82之间约70 kb区间的物理距离内。该区间包含8个开放阅读框(ORF)。其中,第5个ORF(LOC_Os05g26890)被注释为水稻株高基因D1。序列分析发现,潇湘矮的D1基因在第5和12外显子分别有1个碱基的无义替换和3个碱基的缺失,其中第12外显子3个碱基的缺失导致1个赖氨酸的缺失。转基因互补显示D1可以恢复潇湘矮的表型。【结论】潇湘矮控制株高的途径可能与GA_3代谢有关;潇湘矮矮秆小粒表型符合单隐性核基因控制的遗传规律;潇湘矮矮秆小粒性状是由D1基因突变所致。

Editing of Rice Isoamylase Gene ISA1 Provides Insights into Its Function in Starch Formation

Isoamylase 1(ISA1) is an isoamylase-type debranching enzyme which plays a predominant role in amylopectin synthesis. In this study, the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated endonuclease 9(CRISPR/Cas9) system was used to edit ISA1 gene in rice via Agrobacterium-mediated transformation. We identified 36 genetic edited lines from 55 T_0 transgenic events, and classified the mutation forms into 7 types. Of those, two homozygous mutants, cr-isa1-1(type 1, with an adenine insertion) and cr-isa1-2(type 3, with a cytosine deletion) were selected for further analysis. Seed sizes of both cr-isa1-1 and cr-isa1-2 were affected, and the two mutants also displayed a shrunken endosperm with significantly lower grain weight. Electron microscopy analysis showed that abnormal starch granules and amyloplasts were found in cr-isa1-1 and cr-isa1-2 endosperm cells. The contents of total starch, amylose and amylopectin in the endosperm of the cr-isa1 mutants were significantly reduced, whereas sugar content and starch gel consistency were observably increased compared to the wild-type. The gelatinization temperature and starch chain length distributions of the cr-isa1 mutants were also altered. Moreover, transcript levels of most starch synthesis-related genes were significantly lower in cr-isa1 mutants. In conclusion, the results indicated that gene edition of ISA1 affected starch synthesis and endosperm development, and brought potential implications for rice quality breeding.

Differences of Physicochemical Properties Between Chalky and Translucent Parts of Rice Grains

Rice grain chalkiness is an important characteristic,but the difference between chalky and translucent parts in grains is still unclear.Here,we investigated the differences of flour made from the chalky or translucent part of rice grains in three indica and three japonica rice varieties.The chalky flour had significantly lower amylose and protein contents and looser starch granule morphology,and starches in the chalky flour had higher relative crystallinity,higher short chain content but lower long chain content than those in the translucent flour.The water states,determined with nuclear magnetic resonance,differed between the chalky and translucent flour after soaking,cooking and retrograding,and the chalky flour had more bound and free water but less constructural water than the translucent flour.Mostly,the chalky flour had lower viscosity and shorter gel consistency,but higher onset temperature and gelatinization enthalpy than the translucent flour.The results indicated that starch granule morphology would be more indicative than other attributions on pasting and gelatinization properties of chalky and translucent parts of rice grains.

Improved Eating and Cooking Quality of indica Rice Cultivar YK17 via Adenine Base Editing of Wx^(a)Allele of Granule-Bound Starch Synthase I(GBSS I)

Amylose content(AC)is the key determinant of eating and cooking quality(ECQ)of rice.The major Wxa allele of granule-bound starch synthase I(GBSS I)in indica rice produces higher AC,making rice hard and dry after cooking.Recent work has improved ECQ of japonica rice via clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9(CRISPR/Cas9)or cytosine base editing(CBE)techniques.

NRL3 Interacts with OsK4 to Regulate Heading Date in Rice

NRL3 is essential for the growth and development of rice leaves.In this study,we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions.The yeast two-hybrid and the bimolecular fluorescence complementation proved that NRL3interacts with OsK4,a Snf1-related kinase.OsK4 localized to the nucleus and expressed in various rice tissues.The rhythmic expression pattern of Os K4 was similar to NRL3 under long daylight and short daylight conditions.Knock-out mutants of Os K4 exhibited early heading under long daylight conditions,indicating that it acts as a negative regulator of heading date in rice.Interestingly,the OsK4 mutant under the nrl3 mutant background rescued the late heading phenotype of nrl3 under long daylight conditions,suggesting that Os K4 functions downstream of NRL3.Moreover,both NRL3 and Os K4 controlled heading date through regulating the expression of Hd3a and RFT1 genes.These findings shed light on the heading date regulation in rice and provide a sound theoretical base to improve regional adaptability of rice.

一个调控水稻叶绿素合成基因wl-1的精细定位

为改良优异两系不育系株1S (Z1S)的株型特征,利用甲基磺酸乙酯(EMS)诱变技术处理株1S (Z1S),得到一个苗期为白条纹的突变体,命名为wl-1。以该突变体与粳稻品种日本晴杂交,得F1种子,进而获得自交F2群体。遗传分析表明wl-1受单个隐性基因控制。利用图位克隆技术将wl-1初定位于水稻第3号染色体上RM15851和RM15880两个标记之间。进一步扩大遗传定位群体,最终将wl-1精细定位于标记inedl3和indel4之间的122 kb区域内。生物信息学分析表明该区域有12个ORF。对这12个ORF编码区逐个测序分析表明,其第10个ORF (LOC-03g52170),编码4-羟基-3-甲基丁-2-烯基二磷酸还原酶的第2个外显子上的第165位碱基处存在1个碱基A替换为T的突变。基因表达分析表明,在幼苗期与野生型株1S相比,突变体中LOC-03g52170的表达量显著低于相应的野生型;同时突变体中叶绿素合成相关基因、光合作用相关基因以及叶绿体发育相关基因的表达量发生了显著变化。对叶色基因wl-1 (LOC-03g52170)的挖掘,有利于进一步阐释叶绿体和叶绿素合成的生物学机理,同时为水稻高光效育种提供理论和技术支撑。