Identification and characterization of a novel NAC-like gene in chrysanthemum (Dendranthema lavandulifolium).

KEY MESSAGE: A NAC -like gene named DlNAC1 was identified in chrysanthemum and characterized; it may be involved in regulation of response to abiotic stressors, especially in tolerance to drought and salinity. NAC transcription factors in plants play crucial roles in tolerance to abiotic stressors, and overexpression of the NAC gene in Arabidopsis has been demonstrated to lead to improved drought tolerance. Functions of the NAC genes in chrysanthemum, however, remain poorly understood. In this study, a NAC-like gene named DlNAC1 was identified in chrysanthemum (Dendranthema lavandulifolium) and characterized. Phylogenetic analysis indicated that DlNAC1 contains a typical NAC domain and belongs to the ONAC022 subgroup. According to the subcellular localization and yeast one-hybrid assay, the DlNAC1 protein is localized to nuclei and has a transcription activation ability. Moreover, quantitative real-time PCR analyses showed that DlNAC1 was induced by low-temperature, high-salinity, and drought conditions (separately), but not by abscisic acid (ABA) and heat shock. In these experiments, the downstream genes of NAC transcription factors were found to be up-regulated, including stress-responsive genes KIN1 and AMY1. To further explore the effects of DlNAC1 in response to abiotic stressors, DlNAC1 was overexpressed in tobacco, and these transgenic plants showed significantly enhanced tolerance to drought and salinity. This study suggests that in chrysanthemum, the DlNAC1 gene is involved in regulation of the response to abiotic stressors, especially in tolerance to drought and salinity.

Development of a sensitive molecular detection assay for mango malformation disease caused by Fusarium mangiferae.

OBJECTIVES: To develop a sensitive and specific molecular assay for detection of mango malformation disease (MMD), which is caused primarily by Fusarium mangiferae. RESULTS: We screened 100 ISSR primers and identified one (UBC888) that directed the stable amplification of a specific gene fragment of 479 bp (GenBank accession number KJ526382). Based on the DNA sequence of this fragment, a pair of SCAR primers (W342 and W1772) were designed to amplify another gene fragment of 1376 bp (GenBank accession number KJ526383), demonstrating the successful conversion of an ISSR marker to a SCAR marker. An effective and simple detection assay for MMD was established based on this pair of PCR primers, with a high level of specificity and sensitivity to the DNA of F. mangiferae and other species of Fusarium both in vitro and in vivo. It can detect as little as 10 pg fungal DNA from the DNA of mango's tissues. CONCLUSIONS: Our assay provides a practical method for the early diagnosis so that proper prevention of the mango malformation disease can be developed.

Genome-wide identification of calcium-dependent protein kinases in soybean and analyses of their transcriptional responses to insect herbivory and drought stress.

Calcium-dependent protein kinases (CDPKs) are plant-specific calcium sensors that play important roles in various aspects of plant physiology. Here, we investigated phylogenic relationships, chromosomal locations, gene structures, and tissue-specific, herbivory- and drought-induced expression profiles of soybean (Glycine max) GmCDPKs. Fifty GmCDPK genes were identified, which phylogenetically grouped into 4 distinct clusters and distributed across 13 sub-clusters. Individual classes of GmCDPKs harbor highly conserved mRNA splicing sites, and their exon numbers and lengths were consistent with the phylogenetic relationships, suggesting that at least 13 ancestral CDPK genes had emerged before the split of monocots and eudicots. Gene expression analysis indicated that several GmCDPKs were tissue-specific expressed. GmCDPKs' transcript levels changed after wounding, exhibited specific expression patterns after simulated Spodoptera exigua feeding or soybean aphid (Aphis glycines) herbivory, and were largely independent of the phytohormones jasmonic acid and salicylic acid. The most pronounced transcriptional responses were detected after drought and abscisic acid treatments with more than half of all GmCDPKs being upregulated, suggesting their important roles during abiotic stress responses in soybean. Our data provide an important foundation for further functional dissection of GmCDPKs, especially in the context of soybean-insect interactions and drought stress adaptation.

[Bioactivity of volatile oils from Myoporum bontioides on Plutella xylostella].

This study showed that the volatile oils from Myoporum bontioides had a significant repellent action on Plutella xylostella. When Plutella xylostella adults entered into the 4-arm selective olfactometer, the preferred times and average staying duration, in the order from more to less, were 3, 1, 4, and 2 arms, which showed a tendency of keeping away from the treatment arms. The males were more sensitive to the volatile oils than the females, when the velocity of flow was 200 ml.min-1. On the first day of the 3rd bioassay, the oviposition deterrent rate and IIPC of the volatile oils on Plutella xylostella adults was 94.48% and 0.0552, respectively. A liquid component of the volatile oils from Myoporum bontioides was isolated, purified, and identified as myoporone.

[Bioactivity of Myoporum bontioides extracts to Plutella xylostella].

The bioactivity of Myoporum bontioides extracts to Plutella xylostella was studied with IIPC as evaluated index. The results showed that petroleum ether and chloroform extracts had a higher activity than ethyl acetate and alcohol extracts. At 0.01 gDW x ml(-1), the ODR of petroleum ether and chloroform extracts was 84.69% and 79.90%, and 76.47% and 45.70% after treated 1d and 3d, while the IIPC was 0.1565 and 0.2055, respectively. Provided with a higher concentration of 0.05 gDW x ml(-1), the ODR was 88.52% and 72.25%, and 87.33%, 58.37%, while the IIPC was 0.1125 and 0.2620, respectively. From the chloroform extract of Myopdrum Bontioides, three flavonoids, 2, 3-dihydro-5, 7-dihydroxy-2-phenyl-4H-1-Benzopyran-4-one (I), 3, 5, 7-trihydroxy-2-phenyl-4H-1-Benzopyran-4-one (II) and 5, 7-dihydroxy-3-methoxy-2-(4-methoxyphenyl)-4H-1-Benzopyran-4-one (III), were isolated, and their structure were identified based on the analyses of physical and spectrum data. Among these compounds, (II) had a better bioactivity to Plutella xylostella.