39 research outputs found
Phloem cytochemical modification and gene expression following the recovery of apple plants from apple proliferation
Recovery of apple trees from apple proliferation was studied by
combining ultrastructural, cytochemical, and gene expression analyses to
possibly reveal changes linked to recovery-associated resistance. When
compared with either healthy or visibly diseased plants, recovered apple
trees showed abnormal callose and phloem-protein accumulation in their
leaf phloem. Although cytochemical localization detected Ca2+ ions in the
phloem of all the three plant groups, Ca2+ concentration was remarkably
higher in the phloem cytosol of recovered trees. The expression patterns
of five genes encoding callose synthase and of four genes encoding
phloem proteins were analyzed by quantitative real-time reverse transcription-
polymerase chain reaction. In comparison to both healthy and
diseased plants, four of the above nine genes were remarkably upregulated
in recovered trees. As in infected apple trees, phytoplasma
disappear from the crown during winter, but persist in the roots, and it is
suggested that callose synthesis/deposition and phloem-protein plugging
of the sieve tubes would form physical barriers preventing the recolonization
of the crown during the following spring. Since callose deposition
and phloem-protein aggregation are both Ca2+-dependent processes, the
present results suggest that an inward flux of Ca2+ across the phloem
plasma membrane could act as a signal for activating defense reactions
leading to recovery in phytoplasma-infected apple trees.L'articolo é disponibile sul sito dell'editore: http://www.apsjournals.apsnet.or
Intra-varietal variability of Romanesco variety (Vitis vinifera L.)
Most historical sources that describe the presence of Romanesco variety in vine-growing areas of Lazio Region (Italy) highlighted the variability of morphological traits within the variety. This partly justifies the presence of different synonyms, true or presumed, reported by many authors for this grape variety. With the aim of analysing this variability, eight accessions related to the variety, collected in Lazio Region and grown in the DAFNE grape germplasm collection, have been characterized over five productive seasons. The ampelographic description was carried out using 50 OIV morphological descriptors and ampelometric analyses were carried out on mature leaves by SuperAmpelo software. The DNA of the different accessions, extracted from young leaves, was analyzed using 14 microsatellite loci. Furthermore, at harvest, the grapes of each accession were sampled to assess main compositive characteristics. Results showed differences among accessions on some ampelographic descriptors of the mature leaf, of the bunch, and on phenological stages. Microsatellite profiles allowed for classification of the accessions into three distinct groups. Qualitative analysis of the berry skin showed differences among accessions in the content of the main classes of phenolic compounds
Molecular and phylogenetic analysis of MADS-box genes of MIKC type and chromosome location of SEP-like genes in wheat (Triticum aestivum L.).
Transcription factors encoded by MIKC-type
MADS-box genes control many important functions in
plants, including Xower development and morphogenesis.
The cloning and characterization of 45 MIKC-type MADSbox
full-length cDNA sequences of common wheat is
reported in the present paper. Wheat EST databases were
searched by known sequences of MIKC-type genes and
primers were designed for cDNA cloning by RT-PCR.
Full-length cDNAs were obtained by 5 and 3 RACE
extension. Southern analysis showed that three copies of
the MIKC sequences, corresponding to the three homoeologous
genes, were present. This genome organization was
further conWrmed by aneuploid analysis of six SEP-like
genes, each showing three copies located in diVerent homoeologous
chromosomes. Phylogenetic analysis included the
wheat MIKC cDNAs into 11 of the 13 MIKC subclasses
identiWed in plants and corresponding to most genes controlling
the Xoral homeotic functions. The expression patterns
of the cDNAs corresponding to diVerent homeotic
classes was analysed in 18 wheat tissues and Xoral organs
by RT-PCR, real time RT-PCR and northern hybridisation