- 著者
- Takuya Morimoto Takashi Akagi Ryutaro Tao
- 出版者
- The Japanese Society for Horticultural Science
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.MI-060, (Released:2015-04-04)
- 被引用文献数
- 14 24
Flowering plants have developed a genetically determined self-incompatibility (SI) system to maintain genetic diversity within a species. The Solanaceae, the Rosaceae, and the Plantaginaceae have the S-RNase-based gametophytic SI (GSI) system, which uses S-RNase and F-box proteins as the pistil S and pollen S determinants, respectively. SI is associated with culture and breeding difficulties in rosaceous fruit trees, such as apple, pear, and stone fruit species; therefore, researchers in the pomology field have long studied the mechanism and genetics of SI in order to obtain clues to overcome these difficulties. Here, we investigated the evolutionary paths of the S-RNase genes by tracking their duplication patterns. Phylogenetic analysis and estimation of proxy ages for the establishment of S-RNase and its homologs in several rosaceous species showed that the divergence of S-RNase in the subtribe Malinae and the genus Prunus predated the gene in most recent common ancestors of Rosaceae species. Furthermore, the duplicated S-RNase-like genes were accompanied by duplicated pollen S-like F-box genes, suggesting segmental duplications of the S locus. Analysis of the expression patterns and evolutionary speeds of duplicated S-RNase-like genes in Prunus suggested that these genes have lost the SI recognition function, resulting in a single S locus. Furthermore, the S loci in the current Rosaceae species might have evolved independently from the duplicated S loci, which could explain the presence of genus-specific SI recognition mechanisms in the Rosaceae. The results of the present study should be valuable for the future development of artificial SI control and for self-compatible breeding in rosaceous horticultural plant species.
- 著者
- Takuya Morimoto Yunosuke Matsuda Ryo Sekiguchi Akihiro Itai
- 出版者
- The Japanese Society for Horticultural Science
- 雑誌
- The Horticulture Journal (ISSN:21890102)
- 巻号頁・発行日
- pp.UTD-383, (Released:2022-09-30)
- 被引用文献数
- 2
The development of intergeneric hybrids for horticultural crops has been attempted to introduce new quality and resistance traits and to enlarge the gene pool. Interspecific and intergeneric hybridization are often hindered by incompatibility reactions occurring at various stages of hybridization, from early pollination to initial growth, and the reproductive stages of the progeny. In this study, we investigated intergeneric and interspecific cross-compatibility among six species in the tribe Maleae (Rosaceae), namely, Pyrus communis (European pear), P. pyrifolia (Japanese pear), Malus × domestica (apple), Eriobotrya japonica (loquat), Cydonia oblonga (quince), and Pseudocydonia sinensis (Chinese quince). In vivo pollen tube growth tests showed the presence of a postmating, prezygotic barrier in many cross-combinations, in which cross-compatibility was regulated by both genetic distance and crossing direction. Strong hybridization barriers were observed in pollen tube growth and fruit setting when intergeneric hybridization was performed with E. japonica, a species phylogenetically distant from the others studied. Different compatibility reactions in reciprocal crosses were observed in some intergeneric hybridizations; C. oblonga as a pollen donor was incompatible with P. sinensis, whereas the reciprocal cross was compatible, resulting in the development of hybrid seedlings. Furthermore, the pollen tube growth rate differed among Pyrus species when pollinated on the apple pistils, suggesting divergence of cross-compatibility response in a specific linage. Factors affecting intergeneric hybridization are discussed with reference to the genetic distance between species and morphological characteristics such as pistil length. Our comprehensive assessment of intergeneric cross-compatibility will help provide a way to overcome crossing barriers and develop new hybrid crops in the tribe Maleae.