Comparison Of Chloroplast DNA, Chloroplast Structure And RuBP Carboxylase (rubisco) Activity With K，V，T-Type Cytoplasmic Male-sterile Wheat Lines

Cytoplasmic male-sterile (CMS) lines, especially K (Aegilops kotchyi), V (Aegilopsventricosa), and T (Triticum timopheevi) types of cytoplasms, are of high value in heterosisutilization in wheat (Triticum aestivum L.). The aim of this study was to dicuss therelationship between CMS and chloroplast and to reveal the mechanism of CMS byinvestigating chloroplast DNA, chloroplast microstructural characters and RuBP carboxylase(rubisco) activity in CMS male-sterile lines. The experiment was conducted with cultivars ofthe K, V, T-type CMS lines, the common maintainer tai911289and Ji5418, the F1hybridsand the cytoplasmic donors under field conditions. Research was performed from threeaspects:(1) Chloroplast simple sequence repeat (cpSSR) was developed and used to analyzechloroplast genome difference and identify relevant chloroplast DNA primers for testingdifferent cytoplasmic male sterile line.(2) Determined RuBP carboxylase activity encoded bythe chloroplast DNA and nuclear DNA.(3) Investigating the features and expressivedifferences of the chloroplast microstructure of the flag leaf of the flag leaf. The major resultsare as follows:(1) That showed polymorphism between male sterile lines and maintainer lines incpDNA, and specific fragment in the different cytoplasm type male sterile line, this providesevidence of three types of cytoplasm male sterile lines from different sources, and found5specific primers and7specific primers respectively to identify V type and T sterile lines.(2) There is no difference in cpDNA between the male sterile lines and their cytoplasmdonor, except K ji5418, and because of its nature of maternal inheritance also showed nopolymorphism in cpSSR amplified fragment between the male sterile lines and its fertilityrestoration in the F1generation.(3) The chloroplast structure of K, V, T-type CMS lines were anomalous show that theboundaries of grana lamella of the choloraplast of were fuzzy, even disappeared, and also lagbehind normal development. Meanwhile, the thylakoids among grana lamella were underdeveloped and even ruptured, with the whole lamella disordered. But the maintainer line (B)Ji5418’s chloroplast was in good condition and close to the intima, the grana lamella clear andin order, and the thylakoid among grana clearly visible.The number of chloroplasts per cell of the maintainer line was significantly different from K-and V-type (F=40.47, Pr<0.0001), with19.8in K-type and18.4in T-type, respectively. Moreover, the K-and T-type CMS lines hadround chloroplast. The number of chloroplasts per cell in CMS V-type is24.8, which wasobservably higher than that of CMS K and T-type (F=40.47, Pr<0.0001), but did notsignificantly differ from the maintainer line (F=40.47, Pr<0.0001), with the number ofchloroplasts24.1. Besides, the oblong chloroplast was found in CMS V-type CMS line andmaintainer line.(4) The donors of Aegilops kotschyi and Triticum timopheevii had round chloroplast, andoblong in Aegilops ventricos. Their boundaries of grana lamella of the choloraplast of werefuzzy, the thylakoids among grana lamella were under developed and even ruptured. That issimilar to K-, V-, T-type CMS lines, and they have the same source.(5) The three kinds of chloroplasts of (A×R) F1were oblong and close to the cell intimal.Their bi-layer epicyte were clear and cytoplasm were dense. Meanwhile, the cytoplasm wasfilled with grana and the thylakoids among grana were vivid and visible.(6) Not only two sets of male sterile lines of RuBP carboxylase activity was significantlyhigher than the maintainer lines, but also, in the F1generation, with the recovery of fertilityrestorer, its RuBP carboxylase activity is higher than the maintainer lines but lower than therespective male sterile line in standing and flowering period. However, there is no diffierencebetween them in jointing stage. This may because wheat is main on nutritional growth in thisperiod.