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The gene encoding a new extracellular amylopullulanase (type II pullulanase) was cloned from an extremely thermophilic anaerobic archaeon Thermococcus siculi strain HJ21 isolated previously from a deep-sea hydrothermal vent. The functional hydrolytic domain of the amylopullulanase (TsiApuN) and its MalE fusion protein (MTsiApuN) were expressed heterologously. The complete amylopullulanase (TsiApu) was also purified from fermentation broth of the strain. The pullulanase and amylase activities of the three enzymes were characterized. TsiApu had optimum temperature of 95°C for the both activities, while MTsiApuN and TsiApuN had a higher optimum temperature of 100°C. The residual total activities of MTsiApuN and TsiApuN were both 89% after incubation at 100°C for 1 h, while that of TsiApu was 70%. For all the three enzymes the optimum pHs for amylase and pullulanase activities were 5.0 and 6.0, respectively. By analyzing enzymatic properties of the three enzymes, this study suggests that the carboxy terminal region of TsiApu might interfere with the thermoactivity. The acidic thermoactive amylopullulanases MTsiApuN and TsiApuN could be further employed for industrial saccharification of starch. [ABSTRACT FROM AUTHOR]

The receptor-like kinase ERECTA (ER) plays vital roles in plant adaptation under environmental stress including shade avoidance in Arabidopsis. In our previous study, we identified four ER paralogues in soybean (GmERs) that showed high similarities to Arabidopsis ER. Each GmER was predicted to generate diverse alternative splicing variants. However, whether soybean GmERs contribute to shade avoidance is unknown. Here we report our characterization of GmERs in response to shading. Promoter::GUS staining analysis shows that expression of GmER paralogous genes was differentially induced under shade stress. Further analyses show that GmERa.1 and GmERa.2 exhibit a larger distinction in length than the other GmER variants. GmERa.2 has the shortest length of amino acid with only 15 leucine-rich repeats which is the part of the extracellular domain of GmERa.1. Overexpression of GmERa.2 fully rescued the hypocotyl length, leaf area and petiole length, and the sensitivity of the hypocotyl of Arabidopsis mutant er-3 to shading, suggesting that the truncated extracellular domain of GmERa might contribute importantly to shade avoidance. [ABSTRACT FROM AUTHOR]