No abstract

Analysis of cDNA-AFLP was used to study the genes expressed in zygotic and somatic embryogenesis of Musa acuminata Colla ssp. malaccensis, and a comparison was made between their differential transcribed fragments (TDFs) and the sequenced genome of the double haploid- (DH-) Pahang of the malaccensis subspecies that is available in the network. A total of 253 transcript-derived fragments (TDFs) were detected with apparent size of 100–4000 bp using 5 pairs of AFLP primers, of which 21 were differentially expressed during the different stages of banana embryogenesis; 15 of the sequences have matched DH-Pahang chromosomes, with 7 of them being homologous to gene sequences encoding either known or putative protein domains of higher plants. Four TDF sequences were located in all Musa chromosomes, while the rest were located in one or two chromosomes. Their putative individual function is briefly reviewed based on published information, and the potential roles of these genes in embryo development are discussed. Thus the availability of the genome of Musa and the information of TDFs sequences presented here opens new possibilities for an in-depth study of the molecular and biochemical research of zygotic and somatic embryogenesis of Musa.

Pepper plants with viral symptoms were collected in the Yucatan Peninsula, Mexico (YPM) with the objective to characterize the partial identity and the genetic and phylogenetic relationship of the begomoviruses infecting different pepper species, including <em>Capsicum chinense</em>, various <em>C. annuum</em> landraces, <em>C. frutescens</em>, <em>C. a</em>. var. <em>aviculare</em>, as well as some weeds. The leaf samples were collected during two severe whitefly infestation seasons. Total genomic DNA from the sampled plants was extracted and a fragment of the begomoviruses was amplified using universal primers. Amplicons obtained were sequenced and sequences were used for genetic and phylogenetic analysis. Our results demonstrate that 90.1 % of the total sampled plants (151) were infected with begomoviruses. The data identified Pepper golden mosaic virus (PepGMV) as the most frequent species found within cultivated, semi-cultivated, and wild-analyzed samples. In addition, sequence analysis indicates the presence of <em>Euphorbia mosaic virus-Yucatán Peninsula</em> (EuMV-YP) infecting a Habanero chili plant, as well as the predominance of PepGMV in different weed plant species. Genetic variation based on nucleotide distance analysis from partial DNA-A begomovirus sequences indicated that the PepGMV isolates were closely related among them sharing 95 to 99% nucleotide sequence identity. Data showed that begomovirus that infected the sampled plants included the partially identified species of PepGMV, <em>Pepper huasteco yellow vein virus</em> (PHYVV), <em>Tomato severe leaf curl virus</em> (ToSLCV), <em>Tomato yellow leaf curl virus</em> (TYLCV) and EuMV-YP.