Results for “autotetraploidy”

PubMed1977

The karyotype of the tetraploid species Xenopus vestitus Laurent (Anura: pipidae).

Xenopus vestitus possesses 72 chromosomes, wherease in the majority of known Xenopus species there are 2n = 36. During meiosis, 36 bivalents are usually observed at metaphase I and 36 chromosomes at metaphase II. Arranged according to size and centromere position, the chromosomes form the same basic morphologic groups typical of the genus Xenopus. However, the groups are composed of quartets of four similar chromosomes instead of diploid pairs of homologs. The exception to this arrangement involves chromosomes bearing secondary constrictions, which in X. vestitus are represented by two different pairs of homologs, one of which shows, in 39% of the observed mitoses, somatic association and is, therefore, considered to carry the nucleolar organizer. X. vestitus represents either a case of ancient autotetraploidy or, more likely, one of allotetraploidy of more modern origin.

Animals↗

PubMed2026

A robust biotechnology induces artificial genomic duplication via transient RNAi-mediated suppression of OSD1 in rice.

Ploidy manipulation is a crucial strategy for generating germplasm in crop breeding. However, artificial genomic duplication, often induced by colchicine treatment, is associated with toxicity and unpredictability. Although mutations in OSD1 have shown promise for inducing genomic duplication, the instability of ploidy across generations limits their practical application. In this study, we developed a Plant Polyploidization via Gene Interference (PPGI) system that utilizes transient RNAi-mediated suppression of OSD1 to efficiently induce artificial genomic duplication, demonstrating obvious potential for producing autotetraploids. We first validated this system by successfully generating PPGI-induced autotetraploid plants from the Taichung65 cultivar. These PPGI-induced plants exhibited notable differences from Taichung65 but resembled the existing Taichung65-4x line obtained through colchicine treatment. Haplotype analysis indicated that the OSD1 RNAi fragment is conserved across 2,908 rice cultivars. Consequently, we employed the same PPGI vector to develop autotetraploid lines from various germplasms, including another japonica cultivar, seven indica cultivars, and one Oryza rufipogon line. The probability of genomic duplication achieved by our PPGI method was higher than that obtained by colchicine treatment. Typically, autotetraploid lines exhibit severe sterility in the first generation following polyploidization. Leveraging fertile neo-tetraploid rice and the PPGI system, we designed and verified two strategies to directly induce fertile autotetraploid germplasms in the first generation, thereby substantially shortening the breeding cycle. Our method provides a universal, efficient, and non-toxic approach for inducing autotetraploid rice germplasms and contributes to enriching fertile autotetraploid rice germplasm resources.

OSD1↗