Rice blast caused by Magnaporthe oryzae poses a major threat to rice production worldwide. The utilization of host resistance (R) genes is considered to be the most effective and economic means to control rice blast. Here, we show that the japonica landrace Yangmaogu (YMG) displays a broader spectrum of resistance to blast isolates than other previously reported broad-spectrum resistant (BSR) cultivars. Genetic analysis suggested that YMG contains at least three major R genes. One gene, Pi64, which exhibits resistance to indica-sourced isolate CH43 and several other isolates, was mapped to a 43-kb interval on chromosome 1 of YMG. Two open reading frames (NBS-1 and NBS-2) encoding nucleotide-binding site and leucine-rich repeat proteins were short-listed as candidate genes for Pi64. Constructs containing each candidate gene were transformed into three susceptible japonica cultivars. Only transformants with NBS-2 conferred resistance to leaf and neck blast, validating the idea that NBS-2 represents the functional Pi64 gene. Pi64 is constitutively expressed at all development stages and in all tissues examined. Pi64 protein is localized in both the cytoplasm and nucleus. Furthermore, introgression of Pi64 into susceptible cultivars via gene transformation and marker-assisted selection conferred high-level and broad-spectrum leaf and neck blast resistance to indica-sourced isolates, demonstrating its potential utility in breeding BSR rice cultivars.

Low temperature induces diapause in locusts. However, the physiological processes and initiation mechanism of diapause are not well understood. To understand the molecular basis of diapause, ‘omics’ analyses were performed to examine the differences between diapause and non-diapause eggs at both transcriptional and translational levels. Results indicated that a total of 62,241 mRNAs and 212 proteins were differentially expressed. Among them, 116 transcripts had concurrent transcription and translation profiles. Up-regulated genes related to diapause included glutathiones-S-transferase et al., and down-regulated genes including juvenile hormone esterase-like protein et al. KEGG analysis mapped 7,243 and 99 differentially expressed genes and proteins, to 83 and 25 pathways, respectively. Correlation enriched pathways indicated that there were nine identical pathways related to diapause. Gene Ontology analysis placed these genes and proteins into three categories, and a higher proportion of genes related to metabolism was up-regulated than down-regulated. Furthermore, three up-regulated pathways were linked to cryoprotection. This study demonstrates the applicability of high-throughput omics tools to identify molecules linked to diapause in the locust. In addition, it reveals cellular metabolism in diapause eggs is more active than in non-diapause eggs, and up-regulated enzymes may play roles in cryoprotection and storing energy for diapause and post-diapause stages.

No abstract

No abstract

Photoperiod is one of the most important maternal factors with an impact on the offspring diapause induction of Locusta migratoria. Previous studies have shown that forkhead box protein O (FOXO) plays an important role in regulating insect diapause, but how photoperiod stimulates maternal migratory locusts to regulate the next generation of egg diapause through the FOXO signaling pathway still needs to be addressed. In this study, the transcriptomes of ovaries and fat bodies of adult locusts under a long and short photoperiod were obtained. Among the total of 137 differentially expressed genes (DEGs) in both ovaries and fat bodies, 71 DEGs involved in FOXO signaling pathways might be closely related to diapause induction. 24 key DEGs were selected and their expression profiles were confirmed to be consistent with the transcriptome results using qRT-PCR. RNA interference was then performed to verify the function of retinoic acid induced protein gene (rai1) and foxo. Egg diapause rates were significantly increased by RNAi maternal locusts rai1 gene under short photoperiods. However, the egg diapause rates were significantly decreased by knock down of the foxo gene in the maternal locusts under a short photoperiod. In addition, reactive oxygen species (ROS) and superoxide dismutase (SOD) activities were promoted by RNAi rai1. We identified the candidate genes related to the FOXO pathway, and verified the diapause regulation function of rai1 and foxo under a short photoperiod only. In the future, the researchers can work in the area to explore other factors and genes that can promote diapause induction under a long photoperiod.

Entomopathogenic fungus Metarhizium anisopliae obtain survival benefit meanwhile promote the nutrient absorption of root as an endophyte. However, little is known concerning molecular mechanisms in the process. We performed the transcriptome sequencing of A. hypogaea roots inoculated M. anisopliae and pathogenic Fusarium axysporum, respectively. There were 81323 unigenes from 132023 transcripts. Total 203 differentially expressed genes (DEGs) respond to the two fungi, including specific 76 and 34 DEGs distributed respectively in M. anisopliae and F. axysporum treatment. KEGG pathway enrichment for DEGs showed the two top2 were signal transductions of plant-pathogen interaction and plant hormone. By qRT-PCR, the mRNA level of 26 genes involved in plant-fungus interaction confirmed the reliability of the RNA-Seq data. The expression pattern of the key DEGs on jasmonic acid (JA) or salicylic acid (SA) signaling pathway presented regulating consistency with JA or SA concentration detected by HPLC-MS. Those significantly stronger down-regulated DEGs by M. anisopliae thanby F. axysporum linking to hypersensitive response and negative regulation of defense, and those specific up-regulated genes in M. anisopliae treatment may predict that the less immunity is conducive to symbiosis F. axysporum may trigger JA-mediated defense regulated by ERF branch of JA signaling pathway, whereas M. anisopliae does not.

No abstract

The spotted alfalfa aphid (Therioaphis trifolii (Monell)) is a known destructive pest that can significantly reduce alfalfa yields. Two differentially up-regulated alfalfa trypsin inhibitors ‘Msti-94’ and ‘Msti-16’ in transcriptome were verified in terms of their mRNA levels using RT-qPCR. The prokaryotic expression vector was constructed and its biological functions, including phenotypic and physiological responses, were verified through feeding spotted alfalfa aphids with active recombinant protein mixed with an artificial diet. Gene clone and gene prokaryotic expression confirmed that Msti-94 had a size of 651 bp, encoded 216 amino acids with a predicted protein weight of 23.5 kDa, and a pI value of 6.91. Similarly, the size of Msti-16 was 612 bp, encoded 203 amino acids, and had a predicted protein weight of 22.2 kDa with a pI value of 9.06. We concluded that both Msti-94 and Msti-16 acted as a stomach poison with survival rates reduced to 21.7% and 18.3%, respectively, as compared to the control, where the survival rate was significantly (p < 0.05) higher (60.0%). Aphid reproduction rates were significantly reduced, after 72 h of feeding, in both the Msti-94 and Msti-16 treatments compared to the controls. A concentration of 800 μg/mL (0.8 mg/mL) of recombinant protein and 5000 μg/mL (5 mg/mL) of recombinant expressing bacteria that inhibits the total protease, which ultimately disrupted the activity of trypsin, chymotrypsin, and aminopeptidase.