The B-box (BBX) family of proteins consists of zinc-finger transcription factors with one or two highly conserved B-box motifs at their N-termini.  BBX proteins play crucial roles in various aspects of plant growth and development, including seedling photomorphogenesis, shade avoidance, flowering time, and biotic and abiotic stress responses.  Previous studies have identified many different BBXs from several plant species, although the BBX family members in maize are largely unknown.  Genome-wide identification and comprehensive analysis of maize BBX (ZmBBX) expression and interaction networks would therefore provide valuable information for understanding their functions.  In this study, 36 maize BBXs in three major clades were identified.  The ZmBBXs within a given clade were found to share similar domains, motifs, and genomic structures.  Gene duplication analyses revealed that the expansion of BBX proteins in maize has mainly occurred by segmental duplication.  The expression levels of ZmBBXs were analyzed in various organs and tissues, and under different abiotic stress conditions.  Protein–protein interaction networks of ZmBBXs were established using bioinformatic tools and verified by bimolecular fluorescence complementation (BiFC) assays.  Our findings can facilitate a greater understanding of the complexity of the ZmBBX family and provide novel clues for unravelling ZmBBX protein functions

    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.