Identification of quantitative trait loci for resistance against soybean sudden death syndrome caused by Fusarium tucumaniae

The objective of this work was to identify genomic regions that underlie resistance to Fusarium tucumaniae sp. nov., the causing agent of sudden death syndrome (SDS) in soybean in South America, using a population with a genetic background different from that previously reported for Fusarium virguliforme sp. nov. (F. solani f. sp. glycines), also responsible for SDS in soybean. Although major genes and quantitative trait loci (QTL) for SDS resistance have been identified, little is known about the same disease caused by Fusarium tucumaniae sp. nov., in South America. To identify genetic factors related to resistance to F. tucumaniae and DNA markers associated with them, a QTL analysis was performed using recombinant inbred lines. The map locations of the four loci, here identified, differed from those SDS resistance QTL previously described. It was screened a residual heterozygous line (RHL), which was heterozygous around the most effective QTL, RSDS1, and homozygous for the other genomic regions. The genetic effect of RSDS1 was confirmed using near-isogenic lines (NIL) derived from the RHL. The line which was homozygous for the Misuzudaizu genotype showed resistance levels comparable with that of the line homozygous for the Moshidou Gong 503 genotype

Syntaxonomy and biogeography of the Irano-Turanian mires and springs

Aims: To develop the first comprehensive syntaxonomic classification for patchy montane mire and spring vegetation across the Irano-Turanian phytogeographical region in Iran, Tajikistan and Kyrgyzstan and to explore the effects of the main environmental and geographic gradients on their distribution. Location: Alborz Mountain range (Iran), Pamir-Alai Mountains (Tajikistan) and Tian Shan Mountains (Kyrgyzstan); total area of about 3,000,000 km2. Methods: A database of 1,015 vegetation relevés including a total of 675 vascular and bryophyte taxa was established, covering the large mountains ranges of the Irano-Turanian regions in Iran, Tajikistan and Kyrgyzstan, at altitude ranging from 1,300 to 4,505 m a.s.l. A semi-supervised k-means analysis was performed. Additional analyses were carried out to show differences among predefined vegetation groups in terms of phytogeographical, climatic and compositional factors. Results: Two large groups of mire communities, referable to mires and springs were identified. Twenty associations, one subassociation and four alliances of these wetlands, belonging to three orders and three classes, were defined. Among them, ten associations, one subassociation and two alliances were formally described as new syntaxa. Moreover, a new order Caricetalia orbicularis, that comprises phytogeographically unique vegetation of the Irano-Turanian mires, is proposed. Conclusions: Based on our results and comparison between the Irano-Turanian and other phytogeographical regions, we propose a first comprehensive syntaxonomic synopsis for the IranoTuranian mires and springs. Despite some identical character species and their vicariant nature, the Irano-Turanian, Euro-Siberian and Mediterranean mires and springs show considerable compositional differences. Irano-Turanian wetlands contain a large and distinct set of endemic plant species, which are mixed with Euro-Siberian species in the west and north, but predominate in the eastern locations. They have patchy pattern and scattered distribution and serve as inland hotspots of wetland vegetation in the vast dry landscape of SW and Central Asia