Environmental problems have always received immense attention from scientists. Toxicants pollution is a critical environmental concern that has posed serious threats to human health and agricultural ...production. Heavy metals and pesticides are top of the list of environmental toxicants endangering nature. This review focuses on the toxic effect of heavy metals (cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn)) and pesticides (insecticides, herbicides, and fungicides) adversely influencing the agricultural ecosystem (plant and soil) and human health. Furthermore, heavy metals accumulation and pesticide residues in soils and plants have been discussed in detail. In addition, the characteristics of contaminated soil and plant physiological parameters have been reviewed. Moreover, human diseases caused by exposure to heavy metals and pesticides were also reported. The bioaccumulation, mechanism of action, and transmission pathways of both heavy metals and pesticides are emphasized. In addition, the bioavailability in soil and plant uptake of these contaminants has also been considered. Meanwhile, the synergistic and antagonistic interactions between heavy metals and pesticides and their combined toxic effects have been discussed. Previous relevant studies are included to cover all aspects of this review. The information in this review provides deep insights into the understanding of environmental toxicants and their hazardous effects.
We assembled antennal transcriptomes of pest Monochamus alternatus and its parasitoid Dastarcus helophoroides to identify the members of the major chemosensory multi-gene families. Gene ontology (GO) ...annotation indicated that the relative abundance of transcripts associated with specific GO terms was highly similar in the two species. In chemosensory gene families, we identified 52 transcripts encoding putative odorant-binding proteins (OBPs), 19 chemosensory proteins (CSPs), 10 olfactory receptors (ORs), 8 ionotropic receptors (IRs), 2 gustatory receptors (GRs), and 5 sensory neuron membrane proteins (SNMPs) in these two transcriptomes. Predicted protein sequences were compared with Dendroctonus ponderosae, Tribolium castaneum and Drosophila melanogaster. The results of phylogenetic trees showed that some clusters included only OBPs or CSPs from D. helophoroides, some clusters included only OBPs or CSPs from M. alternatus, while some clusters included OBPs or CSPs from both M. alternatus and D. helophoroides. The identification of the chemosensory genes and the phylogenetic relationship of these genes between two species might provide new ideas for controlling M. alternatus and improving current strategies for biological control.
Female insects oviposit in sites suitable for the development of their offspring. The Oriental armyworm, Mythimna separata is a serious pest of various crops including wheat and prefers to oviposit ...on withered leaves rather than on fresh plant material, which is surprisingly different from other insects. Studies here showed that this oviposition tactic enables avoidance of wheat defence against eggs and emerged larvae. Intact plants responded to M. separata egg deposition by releasing oviposition‐induced plant volatiles including acetophenone, tetradecene and pentadecane after 24 h. Acetophenone was identified as quantitatively accounting for the attraction of the egg parasitoid wasp (Trichogramma chilonis). Leaf jasmonic acid levels significantly increased after M. separata laid eggs, and primed the plant against emerging larvae. In addition, newly emerged M. separata larvae adopted a fast crawling behaviour and starvation tolerance compared with other noctuid larvae, which enhanced the survival of larvae on the withered leaves. The elucidation of this complex and surprising plant‐insect interaction provides the first explanation for a herbivore laying eggs on withered leaves to avoid natural enemies and live‐plant defence against emerging larvae.
Summary statement
Mythimna separata prefers to lay eggs on withered leaves. The result showed that this behaviour avoids plant defence against eggs and the emerged larvae. Ovipositioninduced plant volatiles, especially acetophenone, strongly attracted the egg parasitic wasps.
Chemosensory proteins (CSPs) have great contributions in performing diverse functions in insects. However, physiological appraisal of chemosensory protein genes still remains elusive in insects. We ...studied expression patterns and binding affinities of MsepCSP14, a chemosensory protein, in Mythimna separata. The distinct functions of MsepCSP14 were validated by employing different molecular techniques. The MsepCSP14 had high resemblance of sequence with chemosensory proteins of other insect family members. The MsepCSP14 expression was higher in antennal tissues of females than other tissues. Fluorescence binding assay validated that binding of nine out of 21 ligands to MsepCSP14 was higher at pH 7.4 than at pH 5.0. Three dimensional modeling (3D) and docking analysis predicted that amino acid residues of MsepCSP14 were involved in binding of compounds, and behavior assay displayed that adults of M. separata considerably responded to four volatiles from compounds demonstrating strong binding ability to MsepCSP14. Results of the present study suggest that MsepCSP14 is likely to mediate chemosensory functions in M. separata.
Summary
Soybean (Glycine max) is one of the most important oilseed crops. However, the regulatory mechanism that governs the process of oil accumulation in soybean remains poorly understood.
In this ...study, GmZF392, a tandem CCCH zinc finger (TZF) protein which was identified in our previous RNA‐seq analysis of seed‐preferred transcription factors, was found to function as a positive regulator of lipid production.
GmZF392 promotes seed oil accumulation in both transgenic Arabidopsis and stable transgenic soybean plants by binding to a bipartite cis‐element, containing TG‐ and TA‐rich sequences, in promoter regions, activating the expression of genes in the lipid biosynthesis pathway. GmZF392 physically interacts with GmZF351, our previously identified transcriptional regulator of lipid biosynthesis, to synergistically promote downstream gene expression. Both GmZF392 and GmZF351 are further upregulated by GmNFYA, another transcription factor involved in lipid biosynthesis, directly (in the former case) and indirectly (in the latter case). Promoter sequence diversity analysis showed that the GmZF392 promoter may have been selected at the origin of the Glycine genus and further mildly selected during domestication from wild soybeans to cultivated soybeans.
Our study reveals a regulatory module containing three transcription factors in the lipid biosynthesis pathway, and manipulation of the module may improve oil production in soybean and other oilseed crops.
Insects are highly reliant on their active olfactory system in which odorant binding proteins play a role to selectivity and sensitivity during odour perception and processing. This study sets out to ...determine whether and to which extent the antennal loaded SaveOBP10 in English grain aphid Sitobion avenae, contributes in olfactory processing during host selection. To understand this possible relationship, we purified the SaveOBP10 recombinant protein and performed fluorescence ligand binding tests, molecular docking, RNA interference (RNAi) and behavioural trials. The results showed that SaveOBP10 had strong binding affinities (Ki ≤5 μM) with most of wheat plant volatiles at pH 5.0 as compared to pH 7.4. In Y‐tube olfactometer bioassays, the S. avenae was attracted behaviourally towards pentadecane, butylated hydroxytoluene, tetradecane and β‐caryophyllene however repelled by naphthalene. After RNAi of SaveOBP10, the aphid showed nonattraction towards β‐caryophyllene and nonsignificant behavioural response to pentadecane, butylated hydroxytoluene and tetradecane. Furthermore, the three‐dimensional structure modelling and molecular docking of SaveOBP10 were performed to the volatiles with high binding abilities. Together these findings indicate that SaveOBP10 can bind more strongly to the volatiles that involved in S. avenae behaviour regulation and possibly will contribute effectively in S. avenae integrated pest management.
SaveOBP10 from Sitobion avenae could bind with most of wheat volatiles. SaveOBP10 involved in S. avenae behavior regulation. SaveOBP10's interaction specificity was illustrated by three‐dimensional modeling (3D) and molecular docking.
Insects have evolved highly sensitive olfactory sensory systems to detect plant hosts and mates, with plant volatiles playing an important role in informing insect behavior. Chemosensory proteins ...(CSPs) are thought to play a key role in this process, but in this respect, there is limited information on brown planthopper
Nilaparvata lugens
, one of the most destructive pests of rice. To expand our understanding of CSP function in
N. lugens
we explored expression profiles and binding characteristics of NlugCSP3. The ligands with higher binding affinity were also validated by molecular docking and behavioral assays.
NlugCSP3
mRNA was expressed at relatively higher levels in antennae and abdomen of 3-day-old unmated macropterous males as well as in antennae of 3-day mated macropterous and brachypterous females. Fluorescence competitive binding assays revealed that 5 out of 25 candidate volatiles are strong binders (Ki < 10 μM). Behavioral assays revealed that nonadecane and 2-tridecanone, which have high binding affinities in fluorescence competition-binding assays, displayed strong attractiveness to
N. lugens
. Pursuing this further, molecular docking analysis identified key amino acid residues involved in binding volatile compounds. Overall, our data provide a base for further investigation of the potential physiological functions of CSP3 in
Nilaparvata lugens
, and extend the function of NlugCSP3 in chemoreception of
N. lugens.
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