BACKGROUND The ALOG (Arabidopsis LSH1 and Oryza G1) family of proteins, namely DUF640 (domain of unknown function 640) domain proteins, were found in land plants. Functional characterization of a few ALOG members in model plants such as Arabidopsis and rice suggested they play important regulatory roles in plant development. The information about its evolution, however, is largely limited, and there was no any report on the ALOG genes in Petunia, an important ornamental species. RESULTS The ALOG genes were identified in four species of Petunia including P. axillaris, P. inflata, P. integrifolia, and P. exserta based on the genome and/or transcriptome databases, which were further confirmed by cloning from P. hybrida 'W115' (Mitchel diploid), a popular laboratorial petunia line susceptible to genetic transformation. Phylogenetic analysis indicated that Petunia ALOG genes (named as LSHs according to their closest Arabidopsis homologs) were grouped into four clades, which can be further divided into eight groups, and similar exon-intron structure and motifs are reflected in the same group. The PhLSH genes of hybrid petunia 'W115' were mainly derived from P. axillaris. The qPCR analysis revealed distinct spatial expression patterns among them suggesting potentially functional diversification. Moreover, over-expressing PhLSH7a and PhLSH7b in Arabidopsis uncovered their functions in the development of both vegetative and reproductive organs. CONCLUSIONS Petunia genome includes 11 ALOG genes that can be divided into eight distinct groups, and they also show different expression patterns. Among these genes, PhLSH7b and PhLSH7a play significant roles in plant growth and development, especially in fruit development. Our results provide new insight into the evolution of ALOG gene family and have laid a good foundation for the study of petunia LSH gene in the future.

中文翻译：

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矮牵牛中ALOG基因家族的全基因组鉴定和表征。

背景技术在陆地植物中发现了ALOG（拟南芥LSH1和Oryza G1）蛋白家族，即DUF640（未知功能域640）域蛋白。模型植物（如拟南芥和水稻）中一些ALOG成员的功能表征表明它们在植物发育中起着重要的调节作用。但是，有关其进化的信息非常有限，并且还没有关于重要的观赏物种矮牵牛中ALOG基因的报道。结果基于基因组和/或转录组数据库，在四种矮牵牛属植物中鉴定了ALOG基因，其中包括腋生P. inflata，桔梗P. integrifolia和P. exserta，并通过从P. hybrida'W115克隆进一步证实了该基因。 '（米切尔二倍体），一种易于遗传转化的流行实验室矮牵牛线。系统发育分析表明，矮牵牛ALOG基因（根据其最接近的拟南芥同系物命名为LSHs）分为四个进化枝，可进一步分为八类，并且相似的外显子-内含子结构和基序也反映在同一组中。杂种矮牵牛“ W115”的PhLSH基因主要来源于腋假单胞菌。qPCR分析揭示了其中独特的空间表达模式，表明潜在的功能多样化。此外，在拟南芥中过表达PhLSH7a和PhLSH7b揭示了它们在营养器官和生殖器官发育中的功能。结论矮牵牛基因组包含11个ALOG基因，可分为8个不同的组，并且它们还显示出不同的表达模式。在这些基因中，PhLSH7b和PhLSH7a在植物生长和发育，特别是在水果发育中起重要作用。我们的结果为ALOG基因家族的进化提供了新的见识，并为以后的矮牵牛LSH基因的研究奠定了良好的基础。