| Upland cotton (Gossypium hirsutum L.) is an important economic crop and textilematerials in China. It has strong heterosis. Currently, hybrid seeds are produced mainlythrough hand emasculation-pollination or genetic male sterile techniques. Both methods needa large labor force, making the hybrid seeds more expensive and restricting the utilization ofhybrid seeds in upland cotton. So, creating a novel sterile line of upland cotton, which issuitable for hybrid seeds production, becomes a primary mission of breeders.In this study, we got a novel photosensitive sterile cotton with virescent marker throughspace mutation and further analyzed the characters and sterile mechanism of this mutation.Meanwhile, we first constructed a normalized, full-length cDNA library from cotton anthersand systematically analyzed anther development in upland cotton by digital gene expressionprofiling (DGE). The results were shown as following.1. We fist got a novel photosensitive sterile cotton with virescent marker from CCRI040029through space mutation. After a four-year selection by backcrossing and grafting inAnyang and Sanya, the characters of this mutant had been stable and it was named as CCRI9106. It will perform an excellent germplasm resource for the utilization of heterosis inupland cotton.2. Cotyledon and the top leaf show virescent. By the morphology and chlorophyll cotentanalysis, we found that the virescent leaf turns to be green gradually and is similar to wildtypewhen the top leaf grows to the fifth leaf. So, the virescent does not have a negative effect onplants grown with good field management.3. We constructed two populations of CCRI9106×H559and CCRI9106×CCRI040029. And the F1plants and F2plants were sown and investigated in Anyang. It showedthat both characters, virescent and fertility, were controlled by a single recessive gene.4. We fully analyzed the fertility in Sanya, Anyang and phytotron considering the lightcycle and temperature and found that the CCRI9106was sterile with a13-to14.5-hphotoperiod and fertile with an11-to12.5-h photoperiod when the temperature was higherthan21.5°C. Thus, it could be utilized as a sterile line in long-day areas to produce hybridseeds and as a maintainer line in short-day areas to produce sterile line seeds.5. Through cytological observation about the anthers of CCRI9106and CCRI040029, we found that the pollen grains showed abnormal at uninucleate pollen period under long-dayconditions. And the transcriptome analysis of anthers, which were at tetrad pollen anduninucleate pollen periods, was performed and it indicated that the ubiquitin-proteasomesystem is induced in anthers of CCRI9106at uninucleate pollen period by long-dayconditions, which results in the degradation of cytoplasm protein. So, the pollen grainslost their activities and CCRI9106performed sterile.6. We first constructed a normalized, full-length cDNA library of anthers, which werefrom tetrad pollen period to mature pollen period of CCRI36. Ninety-eight hundred andninety-six high quality ESTs, which assembled into6,643unigenes, were obtained from their3′-ends and were further analyzed. Through bioinformatic analysis, we found many pollenwall related genes and many important biological processes during anther development. Itprovides a mass of reference sequences for anther research in upland cotton.7. We constructed eight digital gene expression profiling libraries of anthers at tetradpollen, uninucleate pollen, binucleate pollen and mature pollen periods along with roots,stems, leaves and embryos. From the analysis, we found10,178anther expressed genes and1,165stage-enriched in anthers. In additional, we found the flavonoid and ascorbate-glutathione cycle should be important during anther development in upland cotton. And manymitosis and hormone response genes were also identified. It would lay a good foundation forthe studying of pollen or anther development and the sterility mechanisms in upland cotton. |
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