Qi L, Friebe B, Gill B S
Department of Plant Pathology, Kansas State University, Manhattan 66506-5502, USA.
Chromosome Res. 2000;8(8):671-6. doi: 10.1023/a:1026785119376.
A recombinant isochromosome i5BLrec of wheat was developed with one arm and the proximal 36% of the other arm of Chinese Spring (CS) origin and the distal 64% of the recombined arm of Triticum turgiduM subsp. dicoccoides origin. The i5BLrec provides an unusual opportunity to analyze the role of the centromere or arm heterozygosity in chromosome prealignment and synapsis during meiosis. In monosomic condition, the i5BLrec formed a ring univalent in 86.8% of the pollen mother cells (PMCs) at meiotic metaphase I. In the disomic condition, the two i5BLrec preferentially paired as a normal bivalent in 74.8% of the PMCs, which differed significantly (p <0.01) from the normal bivalent pairing of 51% observed in diisosomic 5BL chromosomes of the CS (Di5BL(CS)) control plants. In plants with one i5BLrec and a normal 5B(CS), the long arm of 5B(CS) paired with the homologous arm of i5BLrec in 54.4% of the PMCs, and 40.4% of the PMCs had a 5B(CS) univalent and a i5BLrec ring univalent. The implications of the i5BLrec pairing data on the mechanism of Ph1 gene action are discussed.
构建了一个小麦重组等臂染色体i5BLrec，其一条臂以及另一条臂的近端36%源自中国春（CS），重组臂的远端64%源自野生二粒小麦亚种（Triticum turgiduM subsp. dicoccoides）。i5BLrec为分析着丝粒或臂杂合性在减数分裂过程中染色体预排列和联会中的作用提供了一个独特的机会。在单体状态下，i5BLrec在减数第一次分裂中期的86.8%的花粉母细胞（PMC）中形成环状单价体。在二体状态下，两条i5BLrec在74.8%的PMC中优先配对形成正常二价体，这与CS的双等臂5BL染色体（Di5BL(CS)）对照植株中观察到的51%的正常二价体配对有显著差异（p<0.01）。在含有一条i5BLrec和一条正常5B(CS)的植株中，5B(CS)的长臂在54.4%的PMC中与i5BLrec的同源臂配对，40.4%的PMC中有一个5B(CS)单价体和一个i5BLrec环状单价体。讨论了i5BLrec配对数据对Ph1基因作用机制的影响。
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