Molecular Characterization of a New Wheat-Thinopyrum intermedium Translocation Line with Resistance to Powdery Mildew and Stripe Rust

Haixian Zhan,Huijuan Guo,Zhihui Pan,Xiaojun Zhang,Xin Li,Guangrong Li,Zujun Yang,Jin Hu,Juqing Jia,Linyi Qiao,Zhijian Chang

doi:10.3390/ijms16012162

Abstract

A new wheat-Thinopyrum translocation line CH13-21 was selected from the progenies derived from a cross between wheat-Th. intermedium partial amphiploid TAI7047 and wheat line Mianyang11. CH13-21 was characterized by using genomic in situ hybridization (GISH), multicolor-GISH (mc-GISH), multicolor-fluorescence in situ hybridization (mc-FISH) and chromosome-specific molecular markers. When inoculated with stripe rust and powdery mildew isolates, CH13-21 displayed novel resistance to powdery mildew and stripe rust which inherited from its Thinopyrum parent. The chromosomal counting analyses indicated that CH13-21 has 42 chromosomes, with normal bivalent pairing at metaphase I of meiosis. GISH probed by Th. intermedium genomic DNA showed that CH13-21 contained a pair of wheat-Th. intermedium translocated chromosomes. Sequential mc-FISH analyses probed by pSc119.2 and pAs1 clearly revealed that chromosome arm 6BS of CH13-21 was replaced by Thinopyrum chromatin in the translocation chromosome. The molecular markers analysis further confirmed that the introduced Th. intermedium chromatin in CH13-21 belonged to the long arm of homoeologous group 6 chromosome. Therefore, CH13-21 was a new T6BS.6Ai#1L compensating Robertsonian translocation line. It concludes that CH13-21 is a new genetic resource for wheat breeding programs providing novel variation for disease resistances.

Highlights

Powdery mildew caused by Blumeria graminis f. sp. tritici and stripe rust caused by Puccinia striiformis f. sp. tritici are devastating diseases of wheat growing in cold and wet regions of the world [1,2]
Wheat-Th. intermedium derivative line CH13-21 was selected from the BC1F6 progenies of the crosses between wheat-Th. intermedium partial amphiploid TAI7047 and MY11
The results showed that all CH13-21 plants had 42 somatic chromosomes and 21 bivalents at meiotic metaphase I of pollen mother cells (PMCs)

Summary

Introduction

Powdery mildew caused by Blumeria graminis f. sp. tritici and stripe rust caused by Puccinia striiformis f. sp. tritici are devastating diseases of wheat growing in cold and wet regions of the world [1,2]. Developed wheat-Th. intermedium partial amphiploids including Zhong 1 to Zhong 5 [7,8], Otrastsjuskaya [9], TE-3 [10], TAI8335 [11] and TE253 [12] were reported to possess outstanding resistance to powdery mildew and/or stripe rust. It has not been reported so far that any wheat-Th. intermedium translocation lines carry both powdery mildew and stripe rust resistance genes. We determined the chromosomal constitution of the CH13-21 using multiple molecular cytogenetic approaches including the genomic and fluorescence in situ hybridization in combination with functional marker analysis

Morphology and Cytological Observations on CH13-21

Powdery Mildew and Stripe Rust Resistance Testing

Molecular Marker Analysis

Discussion

Plant Materials