Arbuscular Mycorrhizal Fungi as a Salt Bioaccumulation Mechanism for the Establishment of a Neotropical Halophytic Fern in Saline Soils.

is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide.

Arbuscular mycorrhizas and dark septate endophytes associated with grasses from the Argentine Puna.

The Andean Puna is an arid, high-elevation plateau in which plants such as grasses experience high abiotic stress and distinctive environmental conditions. We assessed colonization by arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in the roots of 20 native grass species and examined the relationship between root-associated fungi (AMF and DSE) as a function of the elevation of study sites, the photosynthetic pathways of the grass hosts, and the hosts' life cycles. In general, grasses were co-colonized by AMF and DSE and the colonization by AMF and DSE was not extensive.

Homologous recombination in budding yeast expressing the human RAD52 gene reveals a Rad51-independent mechanism of conservative double-strand break repair.

RAD52 is a homologous recombination (HR) protein that is conserved from bacteriophage to humans. Simultaneously attenuating expression of both the RAD52 gene, and the HR and tumor suppressor gene, BRCA2, in human cells synergistically reduces HR - indicating that RAD52 and BRCA2 control independent mechanisms of HR. We have expressed the human RAD52 gene (HsRAD52) in budding yeast strains lacking the endogenous RAD52 gene and found that HsRAD52 supports repair of DNA double-strand breaks (DSB) by a mechanism of HR that conserves genome structure.

Breeding system diversification and evolution in American Poa supersect. Homalopoa (Poaceae: Poeae: Poinae).

Background And Aims: Poa subgenus Poa supersect. Homalopoa has diversified extensively in the Americas. Over half of the species in the supersection are diclinous; most of these are from the New World, while a few are from South-East Asia.

Colonization of native Andean grasses by arbuscular mycorrhizal fungi in Puna: a matter of altitude, host photosynthetic pathway and host life cycles.

The relationships of altitude, host life cycle (annual or perennial) and photosynthetic pathway (C(3) or C(4) ) with arbuscular mycorrhiza (AM) root colonization were analysed in 35 species of Andean grasses. The study area is located in north-western Argentina along altitudinal sites within the Puna biogeographical region. Twenty-one sites from 3320 to 4314 m were sampled.

Comparative karyotypic analysis in the Alstroemeria hookeri Lodd. (Alstroemeriaceae) complex sensu Bayer (1987).

Alstroemeria L. (Alstroemeriaceae) is an American genus of monocots with two principal distribution centers in Chile and Brazil. In Chile, it is represented by about 32 species, most of them in central Chile, an area known for its high level of endemism.

1+1 = 3: a fusion of 2 enzymes in the methionine salvage pathway of Tetrahymena thermophila creates a trifunctional enzyme that catalyzes 3 steps in the pathway.

The methionine salvage pathway is responsible for regenerating methionine from its derivative, methylthioadenosine. The complete set of enzymes of the methionine pathway has been previously described in bacteria. Despite its importance, the pathway has only been fully described in one eukaryotic organism, yeast.

A novel supermatrix approach improves resolution of phylogenetic relationships in a comprehensive sample of danthonioid grasses.

Phylogeny reconstruction is challenging when branch lengths vary and when different genetic loci show conflicting signals. The number of DNA sequence characters required to obtain robust support for all the nodes in a phylogeny becomes greater with denser taxon sampling. We test the usefulness of an approach mixing densely sampled, variable non-coding sequences (trnL-F; rpl16; atpB-rbcL; ITS) with sparsely sampled, more conservative protein coding and ribosomal sequences (matK; ndhF; rbcL; 26S), for the grass subfamily Danthonioideae.