- 著者
- Nozomi SAITO Jaymee R. ENCABO Sunlu CHEN Gilda JONSON Yuji KISHIMA Il-Ryong CHOI
- 出版者
- Japan International Research Center for Agricultural Sciences
- 雑誌
- Japan Agricultural Research Quarterly: JARQ (ISSN:00213551)
- 巻号頁・発行日
- vol.53, no.1, pp.1-6, 2019-01-01 (Released:2019-01-30)
- 参考文献数
- 25
Rice tungro disease (RTD) is a serious threat to rice production in South and Southeast Asia. RTD is caused by Rice tungro bacilliform virus (RTBV) and Rice tungro spherical virus (RTSV). Coinfection of RTSV and RTBV results in more severe symptoms in African rice Oryza glaberrima than in Asian rice O. sativa. In this study, we examined whether RTBV alone causes more severe symptoms in O. glaberrima than in O. sativa. The examination of 18 accessions of O. glaberrima for RTBV infection indicated that all the O. glaberrima accessions examined were susceptible to RTBV. The reactions to RTBV of three O. glaberrima accessions and two RTBV-susceptible varieties of O. sativa, Taichung Native 1 (TN1) and IR 64, were compared. RTBV accumulation varied depending on the plants and differences in RTBV accumulation were not evident between the two species. However, the O. glaberrima accessions were significantly more stunted by RTBV than IR 64 was. Discoloration of leaves by RTBV was evident in the O. glaberrima plants, but not in the O. sativa plants. Collectively, these results presumably indicated that O. glaberrima is generally more vulnerable to RTBV than O. sativa is.
- 著者
- Shasha Wang Yohei Koide Yuji Kishima
- 出版者
- The Genetics Society of Japan
- 雑誌
- Genes & Genetic Systems (ISSN:13417568)
- 巻号頁・発行日
- vol.97, no.4, pp.177-184, 2022-08-01 (Released:2022-12-17)
- 参考文献数
- 31
The transposon Tam3 of Antirrhinum (snapdragon) has acquired properties that distinguish it from other transposons. Mobile DNA, commonly referred to as a transposable element or transposon, is considered to be synonymous with a selfish factor. That is, a transposable element increases in copy number and moves copies of itself independently of the survival of the host organism. Therefore, the host collectively regulates the transposition activities of most transposable elements in its genome by epigenetic means. However, our analyses of the structure and behavior of Tam3, as shown by the following five results, provide evidence that it does not behave in a selfish manner in relation to the host. 1) Active transposable elements normally increase the abundance of their non-autonomous elements, whereas Tam3 is known to have no non-autonomous elements, and a limited number of around 10 copies of autonomous elements present in the genome have been isolated as active copies. 2) Tam3 does not transpose at 25 ℃, which is the optimal growth temperature for Antirrhinum. Transposition of Tam3 occurs only at low temperatures of about 15 ℃, which is stressful for Antirrhinum. 3) Few strains of Antirrhinum have been found to contain genes that specifically suppress Tam3 transposition. 4) Most of the Tam3 insertions found in Antirrhinum genes do not affect the host genome, and the expression of these host genes is not completely suppressed. 5) Transcription and translation of the Tam3 transposase gene are not epigenetically regulated by the host. These five experimental results constitute evidence that Tam3 retains features that are dissimilar to those of many other transposons and that it does not behave in a selfish manner that is detrimental to the survival of the host. In this review, we consider what kinds of behavior are required if transposons are to establish a mutually beneficial relationship with their hosts, with reference to Tam3.