Soybean (Glycine max (L.) Merr.), a typical short-day plant, is sensitive to photoperiod, which limits the geographical range for its cultivation.  In the flowering pathway regulated by photoperiod, E1, a flowering inhibitor in soybean, plays the dominant role in flowering time regulation.  Two E1 homologs, E1-like-a (E1La) and E1-like-b (E1Lb), play overlapping or redundant roles in conjunction with E1.  In the present study, E1 and E1La/b were simultaneously silenced via RNA interference (RNAi) in Zigongdongdou (ZGDD), an extremely late-flowering soybean landrace from southern China.  As a result, RNAi lines showed a much earlier-flowering phenotype and obvious photoperiod insensitivity compared with wild-type (WT) plants.  In RNAi transgenic plants, the expression levels of flowering inhibitor GmFT4 and flowering promoters GmFT2a/GmFT5a were significantly down- and up-regulated, respectively.  Further, the maturity group (MG) of the RNAi lines was reduced from WT ZGDD’s MG VIII (extremely late-maturity) to MG 000 (super-early maturity), which can even grow in the northernmost village of China located at a latitude of 53.5°N.  Our study confirms that E1 and E1La/b can negatively regulate flowering time in soybean.  The RNAi lines generated in this study, with early flowering and maturity traits, can serve as valuable materials and a technical foundation for breeding soybeans that are adapted to high-latitude short-season regions.

In this study, the hydrolysis of the insecticide ethiprole in buffered solutions at pH 4.0, 7.0 and 9.0, respectively, and the degradation and adsorption-desorption behaviors of ethiprole in five agricultural soil samples from China were investigated. The half-lives under anaerobic conditions were faster than that in the aerobic experiment. Ethiprole was relatively stable under both acidic and neutral conditions while it was readily hydrolyzed under alkaling condition. The sorption of ethiprole on five soils was well described by the linear and Freundlich equation and mainly governed by soil organic matter. The exothermic process of ethiprole adsorption can also be well explained by physical adsorption. A weak adsorption capacity was observed in all soils, which could readily lead to leaching problems.