Chloride salt enhances plant resistance to biotic stresses.

Biotic stresses caused by bacterial and fungal pathogens damage crops; identifying treatments that enhance disease resistance provides important information for understanding plant defenses and sustainable agriculture. Salt stress affects crop yields worldwide; however, studies have focused on the toxic sodium ion, leaving the effects of the chloride ion unclear. In this study, we found that irrigation with a combination of chloride salts (MgCl2, CaCl2, and KCl) suppressed the cell death phenotype of the ceramide kinase mutant acd5. Chloride salt pre-irrigation also significantly limited the cell death caused by Pseudomonas syringae pv maculicola infection and inhibited the multiplication of this bacterial pathogen in a mechanism partially dependent on the salicylic acid pathway. Moreover, chloride salt pre-irrigation improved plant defenses against the fungal pathogen challenge, confining the lesion area caused by Botrytis cinerea infection. Furthermore, the growth of herbivorous larvae of Spodoptera exigua was retarded by feeding on chloride salt irrigated plants. Thus, our data suggest that treatment with Cl- increases broad spectrum resistance to biotic challenges.

Rapid Identification of Dendrobium officinale from Other Species Using 3D Front-Face Fluorescence Technique.

Dendrobium officinale is a rare and endangered perennial herb in China, which have been used in preparing Chinese tonic medicine for hundreds of years. The severe shortage of this herb and high price have caused that many similar plants were processed as an adulterant and it became difficult to distinguish genuine D. officinale by traditional authentication methods. A sensitive, convenient, and specific method for rapid identification of D. officinale is urgently needed. In the present study, 3D front-face fluorescence technique merged with Independent Component Analysis was used to get the "pure" independent fluorescence signals. The overall 3D-FFF spectra were decomposed into seven independent components (IC). To distinguish D. officinale from other species, IC1 and IC4 were chosen as fluorescence markers and the fluorescence intensity (FI) value at 340 nm/ 442 nm (excitation /emission wavelength) of IC1and 315 nm/ 468 nm of IC4 were used to build a linear model for identifying D. officinale successfully. Compared with other Dendrobium species, D. officinale showed much higher FI1 and FI4 value which is a direct criterion for identification. Meanwhile, even though the FI values of D. officinale may fluctuate due to the difference of growing conditions, the relation between FI1 and FI4 amazingly always fit the linear model constructed (FI4 = 9.9046 + 0.6119FI1, R2 = 0.9811). The linear model is an important finding and specific for D. officinale. Based on the FI value and the goodness of fit in the linear model, D. officinale can be identified quickly.