Search

Evaluation of the genetic diversity for six genes in forty animals of the Portuguese indigenous sheep breed (Ovis aries) ""Churra da Terra Quente"" was done. A non-radioactive method to allow single-strand conformation polymorphism (SSCP) detection was optimised, starting from genomic DNA and PCR amplification of seven fragments: exon 1 of the alpha-lactalbumin gene; exons 10 and 11 of the alpha s1-casein gene; exon 7 of the beta-casein gene; exon 4 of the kappa-casein gene; exons 4 and 5 of the growth hormone gene and exon 6 of the growth hormone receptor gene. Polymorphisms were detected in five of the seven PCR products. Only kappa-casein and growth hormone receptor were monomorphic. Alpha-lactalbumin and alpha s1-casein exons showed three conformational patterns, beta-casein and growth hormone exon 4 showed two electrophoretic patterns and growth hormone exon 5 showed five conformational patterns. These data provide evidence that ""Churra da Terra Quente"" has a high genetic variability, which opens interesting prospects for future selection programs and also for preservation strategies. Also, our data show that PCR-SSCP is an appropriate tool for evaluating genetic variability.

Abstract: Recently, members of the MATE family have been implicated in aluminium (Al) tolerance by facilitating citrate efflux in plants. The aim of the present work was to perform a molecular characterisation of the MATE2 gene in bread wheat. Here, we cloned a member of the MATE gene family in bread wheat and named it TaMATE2, which showed the typical secondary structure of MATE‐type transporters maintaining all the 12 transmembrane domains. Amplification in Chinese Spring nulli‐tetrasomic and ditelosomic lines revealed that TaMATE2 is located on the long arm of homoeologous group 1 chromosomes. The transcript expression of TaMATE2 homoeologues in two diverse bread wheat genotypes, Barbela 7/72/92 (Al‐tolerant) and Anahuac (Al‐sensitive), suggested that TaMATE2 is expressed in both root and shoot tissues of bread wheat, but mainly confined to root rather than shoot tissues. A time‐course analysis of TaMATE2 homoeologue transcript expression revealed the Al responsive expression of TaMATE2 in root apices of the Al‐tolerant genotype, Barbela 7/72/92. Considering the high similarity of TaMATE2 together with similar Al responsive expression pattern as of ScFRDL2 from rye and OsFRDL2 from rice, it is likely that TaMATE2 also encodes a citrate transporter. Furthermore, the TaMATE2‐D homoeologue appears to be near the previously reported locus (wPt0077) on chromosome 1D for Al tolerance. In conclusion, molecular cloning of TaMATE2 homoeologues, particularly TaMATE2‐D, provides a plausible candidate for Al tolerance in bread wheat that can be used for the development of more Al‐tolerant cultivars in this staple crop. [ABSTRACT FROM AUTHOR]