Multifaceted roles of zinc finger proteins in regulating various agronomic traits in rice.

Rice is an important cereal crop, which provides staple food for more than half of the world's population. To meet the demand of the ever-growing population in the next few decades, an extra increase in rice yield is an urgent need. Given that various agronomic traits contribute to the yield of rice, deciphering the key regulators involved in multiple agronomic trait formation is particularly important. As a superfamily of transcription factors, zinc finger proteins participate in regulating multiple genes in almost every stage of rice growth and development. Therefore, understanding zinc finger proteins underlying regulatory network would provide insights into the regulation of agronomic traits in rice. To this end, we intend to summarize the current advances in zinc finger proteins, with emphasis on C2H2 and CCCH proteins, and then discuss their potential in improving rice yield.

Impact of transgenic insect-resistant maize HGK60 with Cry1Ah gene on community components and biodiversity of arthropods in the fields.

In recent years, transgenic technology has developed rapidly, but the risk of the environmental release of transgenic organisms is still a key issue. Research on the impact on biodiversity is an effective way to objectively evaluate the risk. By taking transgenic maize HGK60 with insect-resistant gene Cry1Ah and common maize Zheng 58 as control, a 2-year experiment of arthropod community biodiversity in fields of them were studied using three methods.in 2019 and 2020. The results showed that a total of 124 species and 38537 individuals were observed from the experiment, belonging to 11 orders and 40 families. There was no significant difference in the individual number and species number of herbivorous, predatory and parasitic groups in the two kinds of maize in two years. Only the individual number of HGK60 was significantly higher than that of common maize Zheng 58 at heading stage in 2019. And the percentages of individual number and species number in different groups were basically the same in the two kinds of maize at each stage in two years. Analyses of Richness index, Shannon-Wiener diversity index, Dominance index and Evenness index showed no significant difference between the two kinds of maize in two years. The similarity coefficient of the arthropod community suggested that the arthropod community composition of HGK60 was similar to that of common maize Zheng 58. Furthermore, HGK60 had no significant effect on the relative stability of the arthropod community. These results indicated that despite the presence of a relatively minor difference in arthropod community between the two kinds of maize, the planting of HGK60 had little effect on arthropod community biodiversity. The results provided some data and support for the further studies of environmental risk of transgenic crops.

Comparison of genetically modified insect-resistant maize and non-transgenic maize revealed changes in soil metabolomes but not in rhizosphere bacterial community.

The deliberate introduction of the beneficial gene in crop plants through transgenic technology can provide enormous agricultural and economic benefits. However, the impact of commercialization of these crops on the ecosystem particularly on belowground soil biodiversity is still uncertain. Here, we examined and compared the effects of a non-transgenic maize cultivar and an insect-resistant transgenic maize cultivar genetically engineered with cry1Ah gene from Bacillus thuringiensis, on the rhizosphere bacterial community using 16S rDNA amplicon sequencing and soil metabolome profile using UPLC/MS analysis at six different growth stages. We found no significant differences in bacterial community composition and diversity at all growth stages between the two cultivars. The analysis of bacterial beta-diversity showed an evident difference in community structure attributed to plant different growth stages but not to the plant type. In contrast, the soil metabolic profile of transgenic maize differed from that of the non-transgenic plant at some growth stages, and most of the altered metabolites were usually related to the metabolism but not to the plant-microbe interaction related pathways. These results suggest that genetic modification with the cry1Ah gene-altered maize soil metabolism but had no obvious effect on the rhizosphere bacterial community.

Strain-Modulated Platinum-Palladium Nanowires for Oxygen Reduction Reaction.

Electrocatalytic activity of alloy nanocatalytsts can be manipulated effectively by tuning their physical properties (ensemble, geometric, and ligand effects) to afford optimal surface structure and compositions for proton exchange membrane fuel cell (PEMFC) application. Herein, highly catalytic platinum-palladium nanowires (PtnPd100-n NWs) with a subtle lattice strain and Boerdijk-Coxeter helix type morphology are synthesized through a surfactant-free, thermal single phase solvent method. X-ray diffraction results show that PtnPd100-n NWs are exposed through the (111) facets and their shrinking or expanding lattice parameters can be modulated by the alloy compositions. Electrochemical results reveal that their high catalytic activity correlates with the lattice shrinking, facets, and bimetallic compositions, showing higher activity when the ratio of Pt and Pd is ∼78:22, which is further supported by DFT results. Compared to the nanoparticle type platinum-palladium alloyed catalysts with similar metal compositions (PtnPd100-n NPs), the PtnPd100-n NWs exhibit significantly improved electrocatalytic activity and stability for the oxygen reduction reaction. These findings open new strategies to design the highly active and stable alloy nanocatalysts with controllable compositions.

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Transgenic technology has developed rapidly in recent years. The environmental risk of the release of transgenic organisms is still a key issue. Research on the impacts on biodiversity is an effective way to objectively evaluate the risk. By taking transgenic maize HGK60 with insect-resis-tant gene Cry1Ah and common maize Zheng58 as control, we examined the diversity of arthropods and weeds in spring and winter of 2018 in Hainan Province. 43753 arthropods belonging to 69 species, 19 families, and 7 orders were obtained. There was no significant difference in arthropod community composition, structure and ecological indices between HGK60 and Zheng58. Compared with Zheng58, the transgenic insect-resistant maize HGK60 had obvious resistance to wood boring beetles. 16 species of weeds belonging to 8 families were recorded in the field. There was no significant difference in the density and ecological indices of weeds between HGK60 and Zheng58, with almost the same change trends in the whole growth period. Our results suggested that planting transgenic maize HGK60 with insect-resistant gene Cry1Ah did not affect biodiversity of arthropods and weeds. The results provided scientific support for the further studies of environmental risk of transgenic crops.

Involvement of abscisic acid-responsive element-binding factors in cassava (Manihot esculenta) dehydration stress response.

Cassava (Manihot esculenta) is a major staple food, animal feed and energy crop in the tropics and subtropics. It is one of the most drought-tolerant crops, however, the mechanisms of cassava drought tolerance remain unclear. Abscisic acid (ABA)-responsive element (ABRE)-binding factors (ABFs) are transcription factors that regulate expression of target genes involved in plant tolerance to drought, high salinity, and osmotic stress by binding ABRE cis-elements in the promoter regions of these genes. However, there is little information about ABF genes in cassava. A comprehensive analysis of Manihot esculenta ABFs (MeABFs) described the phylogeny, genome location, cis-acting elements, expression profiles, and regulatory relationship between these factors and Manihot esculenta betaine aldehyde dehydrogenase genes (MeBADHs). Here we conducted genome-wide searches and subsequent molecular cloning to identify seven MeABFs that are distributed unevenly across six chromosomes in cassava. These MeABFs can be clustered into three groups according to their phylogenetic relationships to their Arabidopsis (Arabidopsis thaliana) counterparts. Analysis of the 5'-upstream region of MeABFs revealed putative cis-acting elements related to hormone signaling, stress, light, and circadian clock. MeABF expression profiles displayed clear differences among leaf, stem, root, and tuberous root tissues under non-stress and drought, osmotic, or salt stress conditions. Drought stress in cassava leaves and roots, osmotic stress in tuberous roots, and salt stress in stems induced expression of the highest number of MeABFs showing significantly elevated expression. The glycine betaine (GB) content of cassava leaves also was elevated after drought, osmotic, or salt stress treatments. BADH1 is involved in GB synthesis. We show that MeBADH1 promoter sequences contained ABREs and that MeBADH1 expression correlated with MeABF expression profiles in cassava leaves after the three stress treatments. Taken together, these results suggest that in response to various dehydration stresses, MeABFs in cassava may activate transcriptional expression of MeBADH1 by binding the MeBADH1 promoter that in turn promotes GB biosynthesis and accumulation via an increase in MeBADH1 gene expression levels and MeBADH1 enzymatic activity. These responses protect cells against dehydration stresses by preserving an osmotic balance that enhances cassava tolerance to dehydration stresses.

Effects of sublethal herbicides on offspring germination and seedling growth: Redroot pigweed (Amaranthus retroflexus) vs. velvetleaf (Abutilon theophrasti).

The effects of sublethal doses of herbicides on plants cannot be ignored, yet little is known about the effects of sublethal doses of herbicides on the F1 generation of plants. Seed germination and seedling growth of native and invasive plants following the sublethal exposure of parent plants to herbicides were comparatively analyzed in this study. Sublethal atrazine and tribenuron-methyl had carry-over effects on the germination and seedling growth of the F1 generation of invasive redroot pigweed (Amaranthus retroflexus L.) and native velvetleaf (Abutilon theophrasti Medicus), both of which had different responses to the carry-over effects of sublethal herbicide. The germination percentage of the F1 redroot pigweed (decreased) was greater than that of the F1 velvetleaf (increased or not significantly changed) following parental exposure to atrazine or tribenuron-methyl. Atrazine reduced the radical growth of 7-day-old velvetleaf seedlings and decreased the difference in seedling length between velvetleaf and redroot pigweed, while tribenuron-methyl had no significant effects on the growth of 7-day-old velvetleaf seedlings. The herbicide inhibition effect on the germination and growth of F1 velvetleaf and redroot pigweed did not increase as the sublethal dose increased. This study suggests that carry-over effects of sublethal herbicides weaken the growth advantage of the F1 velvetleaf at the seedling stage and may have a more negative influence on progeny population development of native velvetleaf compared with invasive redroot pigweed.

Bioinformatic identification and expression analysis of banana microRNAs and their targets.

MicroRNAs (miRNAs) represent a class of endogenous non-coding small RNAs that play important roles in multiple biological processes by degrading targeted mRNAs or repressing mRNA translation. Thousands of miRNAs have been identified in many plant species, whereas only a limited number of miRNAs have been predicted in M. acuminata (A genome) and M. balbisiana (B genome). Here, previously known plant miRNAs were BLASTed against the Expressed Sequence Tag (EST) and Genomic Survey Sequence (GSS), a database of banana genes. A total of 32 potential miRNAs belonging to 13 miRNAs families were detected using a range of filtering criteria. 244 miRNA:target pairs were subsequently predicted, most of which encode transcription factors or enzymes that participate in the regulation of development, growth, metabolism, and other physiological processes. In order to validate the predicted miRNAs and the mutual relationship between miRNAs and their target genes, qRT-PCR was applied to detect the tissue-specific expression levels of 12 putative miRNAs and 6 target genes in roots, leaves, flowers, and fruits. This study provides some important information about banana pre-miRNAs, mature miRNAs, and miRNA target genes and these findings can be applied to future research of miRNA functions.