EjGASA6 promotes flowering and root elongation by enhancing gibberellin biosynthesis

The Gibberellic Acid-stimulated Arabidopsis(GASA)gene family is involved in the regulation of gene expression and plant growth,development,and stress responses.To investigate the function of loquat GASA genes in the growth and developmental regulation of plants,a loquat EjGASA6 gene homologous to Arabidopsis AtGASA6 was cloned.EjGASA6 expression was induced by gibberellin,and ectopic transgenic plants containing this gene exhibited earlier bloom and longer primary roots since these phenotypic characteristics are related to higher gibberellin content.Transcriptome analysis and qRT-PCR results showed that the expression levels of GA3ox1 and GA20ox1,which encode key enzymes in gibberellin biosynthesis,were significantly increased.Furthermore,we confirmed that EjGASA6 could promote the expression of GA20ox1 via the luciferase reporter system.Overall,our results suggest that EjGASA6 promotes blooming and main-root elongation by positively regulating gibberellin biosynthesis.These findings broaden our understanding of the role of GASAs in plant development and growth,and lay the groundwork for future research into the functions of EjGASA6 in regulating loquat growth and development.

Genome assembly of wild loquat (Eriobotrya japonica) and resequencing provide new insights into the genomic evolution and fruit domestication in loquat

Wild loquats(Eriobotrya japonica Lindl.)provide remarkable genetic resources for studying domestication and breeding improved varieties.Herein,we generate the first high-quality chromosome-level genome assembly of wild loquat,with 45791 predicted proteincoding genes.Analysis of comparative genomics indicated that loquat shares a common ancestor with apple and pear,and a recent whole-genome duplication event occurred in loquat prior to its divergence.Genome resequencing showed that the loquat germplasms can be distinctly classified into wild and cultivated groups,and the commercial cultivars have experienced allelic admixture.Compared with cultivated loquats,the wild loquat genome showed very few selected genomic regions and had higher levels of genetic diversity.However,whole-genome scans of selective sweeps were mainly related to fruit quality,size,and f lesh color during the domestication process.Large-scale transcriptome and metabolome analyses were further performed to identify differentially expressed genes(DEGs)and differentially accumulated metabolites(DAMs)in wild and cultivated loquats at various fruit development stages.Unlike those in wild loquat,the key DEGs and DAMs involved in carbohydrate metabolism,plant hormone signal transduction,f lavonoid biosynthesis,and carotenoid biosynthesis were significantly regulated in cultivated loquats during fruit development.These high-quality reference genome,resequencing,and large-scale transcriptome/metabolome data provide valuable resources for elucidating fruit domestication and molecular breeding in loquat.

Segregation Correlation of SSR Markers and Flower Traits in Aneuploid Tobacco

Few reports have been seen on the segregation of polyploids and on the relationship between the segregation of SSR loci and that of the morphological traits in polyploid progeny. This paper attempted to gain an insight into the segregation of the hexaploid tobacco progeny and to understand the correlation of the segregation of SSR loci with that of the flower morphological traits. The segregation was evaluated with both SSR markers and morphological traits of the flowers. Twenty pairs of SSR primers were screened and a total of 42 SSR loci were identified. Chi-square analysis showed that the segregation ratio of the SSR loci in the aneuploid progeny was between 1:1 and 2:1. Six morphological traits of flowers, including the lengths of the flower and the calyx, the widths of the calyx, the corolla tube and the corolla, and the coloring of the flower, from 180 progeny and 2 progenitor plants, were determined and Chi-square analyzed. All traits were in consistent also with a segregation ratio of 1:1 to 2:1 except the width of the calyx.

植物外源基因组成分鉴定方法的研究进展

具外源基因组成分(外源染色体/染色体片段/基因)植株是目前进行基因组学研究以及作物改良的重要材料。迄今为止,已建立了基于性状观测、染色体分析、特异蛋白、DNA序列4种鉴定外源基因组成分的策略。其中,基于DNA序列的分子标记技术是当前鉴定外源基因组成分的主要手段,文中归纳了用于小麦、甘蓝等重要作物外源基因组成分的分子标记,且对简单重复序列(Simple sequence repeat,SSR)、插入缺失(Insertion-deletion,InDel)、单核苷酸多态性(Single nucleotide polymorphism,SNP)等9种标记进行了系统的比较。相比单一的鉴定方法,组合法更全面精准,文中对各组合法的应用情况进行统计和分析,提供了小麦族、芸薹族等作物的最佳鉴定组合。新一代分子标记InDel、SNP易实现高通量检测,对于外源渗入基因的精细定位展现了一定的优越性。此外,可以考虑一些新鉴定方法的加入,如微阵列比较基因组杂交(Microarray-based comparative genomic hybridization,array-CGH)、抑制差减杂交(Suppression subtractive hybridization,SSH)。