Cloning and molecular characterization of glyceraldehyde-3-phosphate dehydrogenase gene from thermotolerant mushroom, Lentinus polychrous

This study describes the cloning and expression analysis of the heat shock protein gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in thermotolerant mushroom Lentinus polychrous, one of the most widely cultivated commercial edible mushroom in Thailand. The complete GAPDH coding sequence contained 1,011 bp, encoding for a polypeptide of 337 amino acid residues with the calculated molecular mass of 36.2 kDa and pI of 5.64. Southern blot analysis revealed the presence of a single copy of the GAPDH gene in the L. polychrous genome. The putative amino acidsequence of the L. polychrous GAPDH-encoded protein shared significant sequence identity with other GAPDH proteins from basidiomycetes. Phylogenetic analysis clustered the L. polychrous GAPDH protein with other homobasidiomycetes. Expression analysis of the GAPDH gene by RT-PCR showed that this gene was highly induced not only by heat, but also by cold, ethanol and salt stresses. The GAPDH gene was expressed in both mycelia and fruiting bodies, suggesting that the GAPDH gene product is a heat shock protein which might be involved in the developmental phase of the L. polychrous

Screening for eri silkworm (Samia ricini Donovan) ecoraces using morphological characters, growth, yields, and ISSR marker

The selection of eri silkworm ecoraces with high yield and distinct morphological characters is necessary for variety improvement. The five ecoraces SaKKU1, SaKKU2, SaKKU3, SaKKU4 and SaKKU5 were derived mostly by international academic cooperation. They were cultured using castor leaves of TCO 101 cultivar as food plant at 25±2°C, 80±5% R.H. Based on morphological characters, they are similar, except the body of the 5th instar larva of SaKKU1 is clearly covered with more creamy white powder and the mature larva has a shiny dominant yellow color. The duration of the life cycle among ecoraces was also similar; 46-53 days (SaKKU1), 42-53 days (SaKKU2), 42-52 days (SaKKU3), 40-56 days (SaKKU4) and 41-52 days (SaKKU5). SaKKU1 had the highest survival rate at larval stage (1st – 5th instar) (100.00%) and larva (1st – 5th instar) - adult (88.89%), including the predominant heaviest average larva weight of all instars, 0.0317 g (2nd instar), 0.2206 g (3rd instar), 1.0788 g (4th instar), 4.0102 g (5th instar), and 8.9940 g (5 days of 5th instar), which was significantly different (P<0.05) to other ecoraces. Moreover, this ecorace gave the highest average yields: fresh cocoon weight (3.8016 g), pupa weight (3.2532 g), shell weight (0.5287 g), shell ratio (14.01%), fresh cocoon weight/10,000 larvae (38.01 kg), eggs/moth (531.13 eggs), total eggs (6,375.27 eggs) and total hatching eggs (6,006.13 eggs), which was also significantly different (P<0.05) than other ecoraces. Of those properties, especially survival rates and yields, this ecorace (SaKKU1) is favored for further varietal improvement program. In parallel, genetic relationship analysis of eri silkworm ecoraces using inter-simple sequence repeat (ISSR) technique was also carried out. The result revealed from dendrogram analysis that SaKKU1 was the farthest distance than other ecoraces, especially against SaKKU3. Based on all above results, the SaKKU1 ecorace was considered to be the most suitable for heat tolerant variety improvement

Variability of Alternaria Leaf Spot Resistance in Jerusalem Artichoke (<i>Helianthus tuberosus</i> L.) Accessions Grown in a Humid Tropical Region

Alternaria leaf spot is an emerging disease of Jerusalem artichoke (Helianthus tuberosus L.) in tropical regions. The lack of known resistant germplasm sources is an important constraint to development of Jerusalem artichoke varieties with resistance to Alternaria leaf spot. The objectives of this study were to identify variability of Jerusalem artichoke genotypes for resistance to Alternaria leaf spot under field conditions and to investigate the relationships among resistance characters, yield, and yield components for selection of resistant varieties. Ninety six accessions of Jerusalem artichoke were evaluated in replicated trials under field conditions in early rainy and late rainy seasons in Khon Kaen, Thailand during 2014. Parameters evaluated included disease incidence, disease score, disease severity index, area under disease progress curve of disease incidence, area under disease progress curve of disease severity index, number of tubers/plants, tuber size, and fresh tuber yield. The genotypes HEL 335, HEL 256, HEL 317, HEL 308, and JA 86 were identified as sources of leaf spot resistance in both seasons. These genotypes can be used as sources of leaf spot resistance for Jerusalem artichoke breeding programs. HEL 293 and HEL 246 showed susceptibility to leaf spot disease in both seasons and should be used as standard susceptible checks