Authors:A. Rascio, E. Carlino, G. Nicastro, C. Platani, M. Russo, and N. Fonzo
A wheat (Triticum turgidum L. var. durum) mutant, designated k-plus, constitutively possesses high leaf potassium content and light-green leaves. To study the genetic basis of these traits and to find out their association, k-plus mutant was crossed to the wild type (WT) Trinakria, F1 and F2 populations were developed. The flag leaves of parental lines, F1 and F2 progeny were assayed for ion content, at the heading stage. Potassium content was greater in k-plus than in WT; the F1 hybrids behaved like to the WT, in both potassium and leaf colour. The number of genes conditioning leaf potassium content, was not more than one, as estimated by Castle-Wright method. A single recessive locus controls potassium content of k-plus mutant, with the wild type allele completely dominant over the new mutant. Broad sense heritability can be considered sufficient to obtain progress from selection, of k-plus phenotype. Light-green leaf colour was inherited as monogenic recessive allele, which co-segregate with the locus controlling potassium accumulation. Light-green F2 sub-population had, on the average, significantly more potassium content than green F2 sub-population. These preliminary results encourage further physiologic and genetic analysis of k-plus mutant.
Authors:M. F. Vianna, S. Pelizza, M. L. Russo, S. Rodriguez, and A. C. Scorsetti
The diversity of fungal endophytes is poorly known and particularly in the case of Nicotiana tabacum, the literature is limited. The present study assessed and compared the diversity and distribution of endophytic fungi between different organs of tobacco plants. We calculated the relative frequency and rates of colonisation and of isolation of endophytic fungi in roots, stems and leaves, as well as the Shannon–Wiener and Simpson diversity indexes. Similarities between assemblages from the studied organs were also analysed. A total of 1588 endophytic fungal strains assigned to 31 morphospecies were isolated. The highest diversity of endophytes was found in leaves, being Fusarium graminearum and Alternaria botrytis the most common fungal species. This study provides information on the distribution of fungal endophytes inhabiting leaves, stems, and roots of N. tabacum and thus can serve as a starting point for increasing our comprehension on the interactions in which these fungi are involved.