Fast integration and accumulation of beneficial breeding alleles through an AB–NAMIC strategy in wheat

Wheat(Triticum aestivum)is among the most important staple crops for safeguarding the food security of the growing world population.To bridge the gap between genebank diversity and breeding programs,we developed an advanced backcross-nested association mapping plus inter-crossed population(AB-NAMIC)by crossing three popular wheat cultivars as recurrent founders to 20 germplasm lines from a mini core collection.Selective backcrossing combined with selection against undesirable traits and extensive crossing within and between sub-populations created new opportunities to detect unknown genes and increase the frequency of beneficial alleles in the AB-NAMIC population.We performed phenotyping of 590 AB-NAMIC lines and a natural panel of 476 cultivars for six consecutive growing seasons and genotyped these 1066 lines with a 660K SNP array.Genome-wide association studies of both panels for plant development and yield traits demonstrated improved power to detect rare alleles and loci with medium genetic effects in AB-NAMIC.Notably,genome-wide association studies in AB-NAMIC detected the candidate gene TaSWEET6-7B(TraesCS7B03G1216700),which has high homology to the rice SWEET6b gene and exerts strong effects on adaptation and yield traits.The commercial release of two derived AB-NAMIC lines attests to its direct applicability in wheat improvement.Valuable information on genome-wide association studymapping,candidate genes,and their haplotypes for breeding traits are available through WheatGAB.Our research provides an excellent framework for fast-tracking exploration and accumulation of beneficial alleles stored in genebanks.

TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat

Starch is the most abundant substance in wheat(Triticum aestivum L.)endosperm and provides the major carbohydrate energy for human daily life.Starch synthesis-related(SSR)genes are believed to be spatiotemporally specific,but their transcriptional regulation remains unclear in wheat.Here,we investigate the role of the basic helix-loop-helix(bHLH)transcription factor TabHLH95 in starch synthesis.TabHLH95 is preferentially expressed in the developing grains in wheat and encodes a nucleus localized protein without autoactivation activity.The Tabhlh95 knockout mutants display smaller grain size and less starch content than wild type,whereas overexpression of TabHLH95 enhances starch accumulation and significantly improves thousand grain weight.Transcriptome analysis reveals that the expression of multiple SSR genes is significantly reduced in the Tabhlh95 mutants.TabHLH95 binds to the promoters of ADP-glucose pyrophosphorylase large subunit 1(AGPL1-1D/-1B),AGPL2-5D,and isoamylase(ISA1-7D)and enhances their transcription.Intriguingly,TabHLH95 interacts with the nuclear factor Y(NF-Y)family transcription factor TaNF-YB1,thereby synergistically regulating starch synthesis.These results suggest that the TabHLH95-TaNF-YB1 complex positively modulates starch synthesis and grain weight by regulating the expression of a subset of SSR genes,thus providing a good potential approach for genetic improvement of grain productivity in wheat.

8600眼SMILE术中术后并发症观察

目的:观察分析飞秒激光小切口角膜基质透镜取出术(SMILE)术中及术后并发症。方法:回顾性非随机病例研究。选取2015年3月至2019年10月在济南爱尔眼科医院行SMILE矫正且资料完整的患者4386例(8600眼),对术中、术后并发症的发生情况进行分析,并通过问卷调查的方式,进行视觉质量的研究。结果:术中244眼(2.84%)发生并发症,其中负压吸引环脱失12眼(0.14%),不透明气泡层(OBL)154眼(1.80%),微切口出血25眼(0.29%),寻找角膜基质透镜困难1眼(0.01%),非计划分离透镜33眼(0.38%),透镜残留4眼(0.04%),切口撕裂13眼(0.15%),扫描黑区2眼(0.02%)。术后并发症17眼(0.20%),其中早期弥漫性板层角膜炎8眼(0.09%),术后中期免疫性角膜炎9眼(0.10%)。术后3个月后过矫>0.75 D者26眼(0.30%),欠矫>0.75 D者1眼(0.01%);术后需二次增效手术者1眼(0.01%)。术后视觉质量异常主要为术后初期雾视、眩光、光晕,随着时间的推移均明显改善,术后6个月,99.30%的患者对手术的综合评价为非常满意。结论:SMILE治疗近视并发症少,未出现影响视力的严重并发症,但安全有效,患者满意度高。