Identification Of The Wheat -Rye Small-Segment-Translocation Carrying Wheat Fusarum Head Blight Resistance Gene By Molecular Cytology Method

Wheat Fusarium head blight (FHB), caused mainly by Fusarium graminearum and Fusarium culmorum, is one of the most destructive diseases.FHB significantly reduce wheat grain yield and quality. The resistance resource, however, is very poor. Hence, it is becoming the focus in the world to search and identify resistance genes from wheat aliens' species and integrate them into cultivars. When the resistance genes of the wheat aliens' species is integrated into the cultivars disadvantageous genes is integrated following into the cultivars. It is difficult to utilize the foreign resistant genes to FHB, which lead that there is no wheat resistant cultivar to FHB within the wheat cultivars to date, producing highly and culturing widely. However, a new wheat line, R111, derived from self-hybrid or backcross of wheat-rye's monosomic addition lines created and cultured by chromosome engineering, can be resistance to FHB, high yield and good quality. In order to make good use of it, we must clearly know for following questions: Whether the resistance to disease of R111 is stable, whether heredity of R111 is pure and where the FHB resistance gene derives from. The purpose of this study is to answer those questions. After completing a lot studying, the results are shown as follows:1. Wheat line R111 and two control cultivars: SuMai3 and MY11 were changed by the pathogen indoors. It is showed that the infection type (IT) of R111 was lowest (42.5), which was slightly lower than that of SuMai3 (45.0), remarkably lower than that of MY11 (62.5). According to the standard classification system, R111 was up to be Resistance(R). This was higher than the result of National Identification which was moderate resistance (MR).2. Chromosome measurement of root tip cells and the behavior of poll mother cells (PMCs) showed that the number of body cell chromosomes was 42, and at metaphase I, poll mother cell chromosomes formed 21 bivalents, no univalent; at anaphase I (the early stage), the homoeologous chromosomes separated and divided two regions, including 21 chromosomes(each chromosome composing of two sister chromosomes); At anaphase I (the later stage), the homoeologous chromosomes completely separated and directly moved to two cell poles, neither chromosomes fall behind, nor is chromosome bridge; at telophase II (tetrad phase),no microkernel. It was difficult to resist the conclusion that the R111 was already stable; moreover, there was not added or substituted rye chromosome.3. Giemsa C-banding discovered that the control material ChuanNong12 (R59) had two chromosome-arms 1RS/1BL. While the C-bandings of R111 were coincided with the "Chinese Spring" standard karyotype.4. Genome in Situ Hybridization (GISH) analysis indicated those two visible signals on the arms of chromosome 1RS/1BL of the control material ChuanNong12 (R59) and one distinct signal on the centromeric region of chromosome of R111, which possibly was Small-Segment-Translocation between wheat and rye.Based on the above results, we can safety conclude that the FHB resistance gene possibly came from rye, which located on the Small-Segment-Translocation.