Department of Plant Industry, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Yourgene Bioscience, Shu-Lin District, New Taipei City, Taiwan.
PLoS One. 2018 Mar 22;13(3):e0194605. doi: 10.1371/journal.pone.0194605. eCollection 2018.
Carica papaya L. is an important economic crop worldwide and is used as a model plant for sex-determination research. To study the different flower sex types, we screened sex-related genes using alternative splicing sequences (AS-seqs) from a transcriptome database of the three flower sex types, i.e., males, females, and hermaphrodites, established at 28 days before flowering using 15 bacterial artificial chromosomes (BACs) of C. papaya L. After screening, the cDNA regions of the three sex-related loci, including short vegetative phase-like (CpSVPL), the chromatin assembly factor 1 subunit A-like (CpCAF1AL), and the somatic embryogenesis receptor kinase (CpSERK), which contained eight sex-related single-nucleotide polymorphisms (SNPs) from the different sex types of C. papaya L., were genotyped using high-resolution melting (HRM). The three loci were examined regarding the profiles of the third whorl, as described below. CpSVPL, which had one SNP associated with the three sex genotypes, was highly expressed in the male and female sterile flowers (abnormal hermaphrodite flowers) that lacked the fourth whorl structure. CpCAF1AL, which had three SNPs associated with the male genotype, was highly expressed in male and normal hermaphrodite flowers, and had no AS-seqs, whereas it exhibited low expression and an AS-seqs in intron 11 in abnormal hermaphrodite flowers. Conversely, carpellate flowers (abnormal hermaphrodite flowers) showed low expression of CpSVPL and AS-seqs in introns 5, 6, and 7 of CpSERK, which contained four SNPs associated with the female genotype. Specifically, the CpSERK and CpCAF1AL loci exhibited no AS-seq expression in the third whorl of the male and normal hermaphrodite flowers, respectively, and variance in the AS-seq expression of all other types of flowers. Functional mapping of the third whorl of normal hermaphrodites indicated no AS-seq expression in CpSERK, low CpSVPL expression, and, for CpCAF1AL, high expression and no AS-seq expression on XYh-type chromosomes.
番木瓜是一种重要的经济作物，被广泛应用于性别决定的研究中。为了研究不同花的性别类型，我们从三个花性别类型（雄花、雌花和两性花）的转录组数据库中筛选了与性别相关的基因，这些基因是在开花前 28 天使用 15 个番木瓜的细菌人工染色体（BAC）建立的。筛选后，我们对包括短营养期样（CpSVPL）、染色质组装因子 1 亚基 A 样（CpCAF1AL）和体细胞胚胎发生受体激酶（CpSERK）在内的三个与性别相关的基因座的 cDNA 区域进行了基因型分析，这些基因座含有来自不同性别类型的 8 个与性别相关的单核苷酸多态性（SNP）。使用高分辨率熔解（HRM）技术对这些基因座进行了基因型分析。对第三轮进行了如下描述。与三种性别基因型相关的一个 SNP 的 CpSVPL 在缺少第四轮结构的雄性和雌性不育花（异常两性花）中高度表达。与雄性基因型相关的三个 SNP 的 CpCAF1AL 在雄性和正常两性花中高度表达，且没有 AS-seqs，但在异常两性花的内含子 11 中低表达和存在 AS-seqs。相反，心皮花（异常两性花）在 CpSVPL 和 CpSERK 的内含子 5、6 和 7 中表达水平较低，而 CpSERK 含有与雌性基因型相关的四个 SNP。具体而言，CpSERK 和 CpCAF1AL 基因座在雄性和正常两性花的第三轮中均没有 AS-seq 表达，而其他类型的花的 AS-seq 表达存在差异。正常两性花第三轮的功能图谱表明 CpSERK 没有 AS-seq 表达，CpSVPL 表达水平较低，而 CpCAF1AL 在 XYh 型染色体上表达水平较高，且没有 AS-seq 表达。
