Genetic Mechanism and Chromosomal Location of Pollen-Specific Gene(s) in Gossypium

Genetic manipulation of plant reproduction is limited by the lack of knowledge on genes controlling gametophyte development. We have combined the power of haploid analysis with the advanced technique of confocal laser scanning microscopy to identify and understand the genetic mechanism of pollen development in cotton. A study was made on the differential effects of specific chromosomal deficiencies on the morphology of mature cotton pollen. Pollen of the two tetraploid species (G. hirsutum L. and G. barbadense L.) were found to be morphologically distinct. Confocal microscopy was used to construct a three-dimensional image of the fluorochrome-stained pollen grains. Cytogenetically deficient stocks of cotton were used for locating genes for pollen development to chromosomes and chromosome arms. Results indicated that the pollen size and spine pattern were significantly different between TM-1 (G. hirsutum) and 3-79 (G. barbadense). Comparative analysis of pollen morphology of parental and interspecific hybrid, monosomic, and monotelodisomic plants indicated that gene(s) responsible for pollen spine development were located on the long arm of chromosome 12. The segregating nature of pollen morphological features indicated that the gametophytic gene(s) of the microspore partially controlled the pollen size and spine formation during pollen grain development.
Plant Genome research is directed primarily towards linking sporophytic traits with their major controlling genes. One of the major limitations in the genetic manipulation of plant reproductive systems is the [...]