4 research outputs found
Tomato <i>SlMAPK3</i> Modulates Cold Resistance by Regulating the Synthesis of Raffinose and the Expression of <i>SlWRKY46</i>
Mitogen-activated protein kinase (MAPK) cascades and
raffinose
have been observed to increase in plants exposed to cold. However,
it remains elusive whether and how MAPK regulates raffinose synthesis
under cold stress. Here, overexpression of SlMAPK3 promoted the accumulation of galactinol and raffinose under cold
stress, while CRISPR/Cas9-mediated mutants showed the opposite results.
Moreover, SlMAPK3 promoted the expression of SlWRKY46 at low temperatures and interacted with SlWRKY46 protein. Overexpression of SlWRKY46 enhanced cold resistance. Furthermore, SlWRKY46 directly bound to the promoter of SlGols1 to enhance
its expression and promoted the accumulation of raffinose. Virus-induced
gene-silencing (VIGS)-mediated knockdown of SlGols1 remarkably elevated cold sensitivity and reduced raffinose content.
Meanwhile, exogenous supplementation of raffinose could improve the
cold tolerance of tomato plants. Thus, our data indicates that SlMAPK3 modulates cold resistance by regulating raffinose
content and SlWRKY46 expression. SlWRKY46 also promotes the accumulation of raffinose by inducing the expression
of SlGols1.</i
Novel Xylanase from a Holstein Cattle Rumen Metagenomic Library and Its Application in Xylooligosaccharide and Ferulic Acid Production from Wheat Straw
A novel gene fragment containing a xylanase was identified
from
a Holstein cattle rumen metagenomic library. The novel xylanase (Xyln-SH1)
belonged to the glycoside hydrolase family 10 (GH10) and exhibited
a maximum of 44% identity to the glycoside hydrolase from Clostridium thermocellum ATCC 27405. Xyln-SH1 was
heterologously expressed, purified, and characterized. A high level
of activity was obtained under the optimum conditions of pH 6.5 and
40 °C. A substrate utilization study indicated that Xyln-SH1
was cellulase-free and strictly specific to xylan from softwood. The
synergistic effects of Xyln-SH1 and feruloyl esterase (FAE-SH1) were
observed for the release of xylooligosaccharides (XOS) and ferulic
acid (FA) from wheat straw. In addition, a high dose of Xyln-SH1 alone
was observed to improve the release of FA from wheat straw. These
features suggest that this enzyme has substantial potential to improve
biomass degradation and industrial applications
Reduced Drought Tolerance by CRISPR/Cas9-Mediated <i>SlMAPK3</i> Mutagenesis in Tomato Plants
Drought
stress is one of the most destructive environmental factors
that affect tomato plants adversely. Mitogen-activated protein kinases
(MAPKs) are important signaling molecules that respond to drought
stress. In this study, <i>SlMAPK3</i> was induced by drought
stress, and the clustered regularly interspaced short palindromic
repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) system
was utilized to generate <i>slmapk3</i> mutants. Two independent
T1 transgenic lines and wild-type (WT) tomato plants were used for
analysis of drought tolerance. Compared with WT plants, <i>slmapk3</i> mutants exhibited more severe wilting symptom, higher hydrogen peroxide
content, lower antioxidant enzymes activities, and suffered more membrane
damage under drought stress. Furthermore, knockout of <i>SlMAPK3</i> led to up- or down-regulated expressions of drought stress-responsive
genes including <i>SlLOX</i>, <i>SlGST</i>, and <i>SlDREB</i>. The results suggest that <i>SlMAPK3</i> is involved in drought response in tomato plants by protecting cell
membranes from oxidative damage and modulating transcription of stress-related
genes
Biocontrol Activity of <i>Bacillus subtilis</i> Isolated from <i>Agaricus bisporus</i> Mushroom Compost Against Pathogenic Fungi
Bacillus subtilis strain B154, isolated
from Agaricus bisporus mushroom compost
infected by red bread mold, exhibited antagonistic activities against Neurospora sitophila. Antifungal activity against
phytopathogenic fungi was also observed. The maximum antifungal activity
was reached during the stationary phase. This antifungal activity
was stable over a wide pH and temperature range and was not affected
by proteases. Assay of antifungal activity in vitro indicated that
a purified antifungal substance could strongly inhibit mycelia growth
and spore germination of N. sitophila. In addition, treatment with strain B154 in A. bisporus mushroom compost infected with N. sitophila significantly increased the yield of <i>bisporus</i> mushrooms.
Ultraviolet scan spectroscopy, tricine sodium dodecyl sulfate-polyacrylamide
gel electrophoresis, matrix-associated laser desorption ionization
time-of-flight mass spectrometry, and electrospray ionization tandem
mass spectrometry analyses revealed a molecular weight consistent
with 1498.7633 Da. The antifungal compound might belong to a new type
of lipopeptide fengycin