B-box（BBX）基因家族编码的蛋白是由包含锌指结构的转录因子组成，其N端有一个或两个高度保守的B-box基序。BBX蛋白在植物生长发育的各个方面起着至关重要的作用，包括幼苗的光形态发生、避荫、开花时间以及生物和非生物胁迫响应。目前,各国的研究者已经从几种植物中鉴定了BBX的家族成员，然而玉米中的BBX家族成员还知之甚少。通过对玉米BBX家族基因的全基因组鉴定、表达和互作的综合分析，可为了解其功能提供有用信息。本研究共鉴定出36个玉米BBX家族成员，进化分析显示其分布于三个主要分支。在每个主分支中ZmBBXs都具有相似的结构域、基序和基因组结构。基因重复分析表明，玉米BBX蛋白家族的扩张主要是通过片段重复来完成的。利用实时荧光定量PCR技术，本研究分析了ZmBBXs在不同器官组织和不同非生物胁迫条件下的表达。利用生物信息学工具，本研究建立了ZmBBXs蛋白的相互作用网络，并通过双分子荧光互补（BiFC）试验进行了验证。本研究的发现有助于理解ZmBBX家族的复杂性，并为揭示ZmBBX蛋白的生物学功能提供新的线索。

Received  6 June, 2017    Accepted  13 October, 2017

    With increased cultivation of transgenic Bacillus thuringiensis (Bt) cotton in the saline alkaline soil of China, assessments of transgenic crop biosafety have focused on the effects of soil salinity on rhizosphere microbes and Bt protein residues. In 2013 and 2014, investigations were conducted on the rhizosphere microbial biomass, soil enzyme activities and Bt protein contents of the soil under transgenic Bt cotton (variety GK19) and its parental non-transgenic cotton (Simian 3) cultivated at various salinity levels (1.15, 6.00 and 11.46 dS m⁻¹). Under soil salinity stress, trace amounts of Bt proteins were observed in the Bt cotton GK19 rhizosphere soil, although the protein content increased with cotton growth and increased soil salinity levels. The populations of slight halophilic bacteria, phosphate solubilizing bacteria, ammonifying bacteria, nitrifying bacteria and denitrifying bacteria decreased with increased soil salinity in the Bt and non-Bt cotton rhizosphere soil, and the microbial biomass carbon, microbial respiration and soil catalase, urease and alkaline phosphatase activity also decreased. Correlation analyses showed that the increased Bt protein content in the Bt cotton rhizosphere soil may have been caused by the slower decomposition of soil microorganisms, which suggests that salinity was the main factor influencing the relevant activities of the soil microorganisms and indicates that Bt proteins had no clear adverse effects on the soil microorganisms. The results of this study may provide a theoretical basis for risk assessments of genetically modified cotton in saline alkaline soil.

Plants reshape their transcriptomes, proteomes and metabolomes in response to insect damage. In this study, we used suppression subtractive hybridization to investigate the transcriptomes of two cotton varieties (CCRI41 and CCRI23) under Apolygus lucorum damage. From the CCRI23 libraries we obtained 92 transcripts and from the CCRI41 libraries we obtained 96 transcripts. 26 and 63 of the transcripts from CCRI23 and CCRI41, respectively, had known functions. Using reverse transcription PCR, we detected expression profile of genes with known functions. Ultimately, we identified eight significantly regulated genes, including one downregulated and four upregulated genes from the CCRI41 libraries, and one downregulated and two upregulated genes from the CCRI23 libraries. Only the gene encoding the polyphenol oxidase (PPO) is involved in plant defense against insect herbivores, and the others are related to improving tolerance to insect damage. Quantitative real-time PCR was used to study changes in expression levels during A. lucorum damage in CCRI23 and CCRI41. Significantly regulated genes from CCRI23 showed a response in CCRI23 but not response in CCRI41. Similarly, significantly regulated genes from CCRI41 showed a response in CCRI41 but not response in CCRI23. The results showed that, among transcriptomes of cotton varieties, there are different responses to A. lucorum damage.

Sublethal effects of chlorantraniliprole to Helicoverpa armigera (Hübner) larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7 d, the LC10, LC20, LC40, and LC50 values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure (LC10), offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate (R0), intrinsic rate of increase (rm), and gross reproduction rate (GRR) at LC20, LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time (Dt) at LC20, LC40 concentrations as well as gross reproduction rate (GRR) at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.