[Show abstract][Hide abstract] ABSTRACT: A cytoplasmic mutant of Gossypium barbadense L., cyt-V was characterized at the morphological, cellular, genetic and molecular levels using comparison analysis with v7v7, a nuclear virescent mutant to identify molecular effects of the cyt-V mutation. The yellow phenotype was specific only to leaves in the cyt-V mutant (CM-1-90) but the same phenotype was present in both leaves and cotyledons of v7v7, a nuclear virescent mutant, suggesting that cyt-V and v7v7, had different organ-specific gene actions. Chlorophyll and carotenoid levels of CM-1-90, CM-1-90 PS-7 and CM-1-90 v7v7 true leaves were significantly lower than in the true leaves of PS-7 CM-1-90, v7v7 CM-1-90 and PS-7. Anatomical studies of chloroplast showed that CM-1-90, CM-1-90 PS-7 and CM-1-90 v7v7 lacked grana in the thylakoids of the mesophyll cells. This indicated that chlorophyll and carotenoid levels correlated with chloroplast structure. SDS-PAGE analysis of thylakoid preparations revealed decreases of several granalocalized PSII proteins in CM-1-90, CM-1-90 PS-7 and CM-1-90 v7v7. cDNA-AFLP differential display studies identified several differentially expressed transcripts in the leaves of reciprocal crosses (PS-7 CM-1-90, v7v7 CM-1-90 and CM-1-90 PS-7 and CM-1-90 v7v7), including one possessing a high sequence homology to a psbA gene. Western blot analysis further confirmed the absence of D1 protein encoded by psbA in CM-1-90 PS-7 CM-1-90 v7v7 and CM-1-90 true leaves. Overall, we studied cyt-V and v7v7 that both are developmental mutants, as all the virescents of cotton mutants, and as such it was difficult to separate cause and effect in the observation; however, we verified that the source of cyt-V mutation was in chloroplast and elucidated that its gene action was different from v7v7. Results indicated that cyt-V is inherited as a single gene but it affects several chloroplast and nucleus-encoded genes. We identified several transcripts that associated with the cyt-V mutation. This study also suggested that chloroplast-encoded gene products might affect the expression of nuclear genes, possibly at the transcriptional stage.
[Show abstract][Hide abstract] ABSTRACT: We have developed molecular markers tightly linked to Sex1, the gene that determines plant sex in papaya ( Carica papaya L.). Three RAPD products have been cloned and a portion of their DNA sequenced. Based on these sequences SCAR primers were synthesized. SCAR T12 and SCAR W11 produce products in hermaphrodite and male plants and only rarely in females. SCAR T1 produces a product in all papayas regardless of plant sex. SCAR T12 and SCAR W11 showed no recombination in a population of 182 F2 plants from a 'SunUp' by 'Kapoho' cross. Based on these results a PCR-based technique for rapidly and accurately determining the sex of papaya plants was developed using either W11 or T12 to detect the hermaphrodite or male allele and T1, which amplifies a product regardless of sex type, as a positive control. The sexing technique, using SCAR T12 and SCAR T1 as a positive control, was used to correctly predict hermaphrodite papaya plants in a population of seedlings with an overall accuracy of 99.2%.
Theoretical and Applied Genetics 01/2003; 106(1):107-11. · 3.66 Impact Factor
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