Search

Zoysia japonica Steud. is a warm-season lawn grass popular in Korea and elsewhere. They are cultivated in many places such as river banks, roadside, and play grounds. However, there still is a disadvantage of frequent mowing, and the grass grows poorly under the chilly conditions. To develop a grass variety that circumvents these drawbacks, we cloned the chitin-inducible gibberellins-responsive1 gene (CIGR1) from zoysiagrass. The full length of the ZjCIGR1 (Zj; Zoysia japonica Steud.) gene was obtained by 5′/3′ RACE PCR and the phylogenetic tree showed that it belonged to the CIGR1-subgroup in the PAT1-group of GRAS protein family. Expression of the ZjCIGR1 in wild-type plants was confirmed in roots, meristems, leaves, and flowers, especially high in the flowers. The transgenic zoysiagrass was confirmed by PCR using gene-specific primers, phosphinothricin-acetyl-transferase (PAT) strip test, and Southern blot analysis. ZjCIGR1-overexpressing plants acquired tolerance to cold stress displaying morphological phenotypes characteristic of stress resistance. In addition, in the transformants, expression of the ZjCIGR1 as well as cold-regulated (COR) gene was increased compared to the wild-type plants under cold stress condition. These results suggest that ZjCIGR1 gene is an important candidate for regulating cold stress resistance.

Numerous genes are known to regulate the cold response in plants. The ICE1 gene is a regulator of coldinduced transcriptome playing an important role in cold tolerance in Arabidopsis thaliana. Here, the Arabidopsis ICE1 gene was cloned and transformed into A. thaliana and Korean lawn grass (Zoysia japonica) respectively, under the control of a maize ubiquitin promoter. The transgenic Arabidopsis plants showed higher survival rate, less MDA content, and higher levels of proline, SOD, and POD after freezing treatment. In the case of Z. japonica, 43 transgenic plants were produced by Agrobacterium-mediated transformation. Southern blot analysis showed that 9 transgenic lines selected by phosphinothricin (PPT) were transformed with ICE1 independently. Cold treatment significantly induced the transcripts abundant in the up-regulated ZjCBF and ZjDREB1 in transgenic lines OE-18 and OE-19. Meanwhile, transgenic plants showed increased proline level but decreased MDA content and with higher activities of SOD and POD compared with wild type under cold stress. These results suggest that overexpression of the ICE1 gene could improve the antioxidative capacity in conferring cold tolerance to the transgenic zoysiagrass plants.

Zoysiagrass (Zoysia japonica Steud.) is an important turfgrass species used in golf courses and athletic fields. However, zoysiagrass is susceptible to large patch disease caused by Rhizoctonia solani AG2-2 (IV). Chitinases are pathogen-related (PR) proteins induced by viruses, bacteria, and fungi that hydrolyze chitin. Recently, we isolated a class II chitinase gene (Zjchi2) from zoysiagrass. The purified recombinant Zjchi2 showed broad-spectrum activity against various fungi, including R. solani AG2-2 (IV). In the current study, we generated transgenic zoysiagrass overexpressing Zjchi2 and then verified the resistance of transgenic plants to R. solani AG2-2 (IV). Polymerase chain reaction and Southern blot hybridization showed the integration of transgenes in zoysiagrass genomes and constitutive expression of Zjchi2, respectively. Antifungal activity was enhanced significantly in the transgenic zoysiagrass compared with wild-type plants. To our knowledge, this report is the first on the antifungal activity of a class II chitinase in transgenic zoysiagrass.

한국형 잔디에서는 다른 병에 비해 진전 속도가 빠르고 주로 뿌리에서부터 발병하여 잔디를 고사시키고 발병 후 구제하기 매우 어려운 라이족토니아잎마름병(라지패취)이 큰 문제로 대두되고 있다. 라이족토니아잎마름병(라지패취)은 Rhizoctonia solani AG2-2 (IV)병원균에 의해 발생하는데, 이 병원균에 강한 내병성 들잔...

This study aims to establish a system for the rapid discrimination of Zoysia species using metabolite fingerprinting of FT-IR spectroscopy combined with multivariate analysis. Whole cell extracts from leaves of 19 identified Zoysia japonica, 6 identified Zoysia sinica, and 38 different unidentified Zoysia species were subjected to Fourier transform infrared spectroscopy (FT-IR). PCA (principle component analysis) and PLS-DA (partial least square discriminant analysis) from FT-IR spectral data successfully divided the 25 identified turf grasses into two groups, representing good agreement with species identification using molecular markers. PC (principal component) loading values show that the region of the FT-IR spectra are important for the discrimination of Zoysia species. A dendrogram based on hierarchical clustering analysis (HCA) from the PCA and PLS-DA data of turf grasses showed that turf grass samples were divided into Zoysia japonica and Zoysia sinica in a species-dependent manner. PCA and PLS-DA from FT-IR spectral data of Zoysia species identified and unidentified by molecular markers successfully divided the 49 turf grasses into Z. japonica and Z. sinica. In particular, PLS-DA and the HCA dendrogram could mostly discriminate the 47 Z. japonica grasses into two groups depending on their origins (mountainous areas and island area). Considering these results, we suggest that FT-IR fingerprinting combined with multivariate analysis could be applied to discriminate between Zoysia species as well as their geographical origins of various Zoysia species.

Zoysiagrass (Zoysia Japonica Steud.) is used frequently in golf courses and athletic fields. However, Zoysiagrass suffers from large-patch disease caused by Rhizoctonia solani AG2-2 (IV), which results in physical and economic loss. In this study, two full-length chitinase genes encoding pathogen-related proteins were isolated from zoysiagrass. Structural and expression analyses of these genes were carried out. The two isolated chitinases were classified into class Ib (Zjchi1) and class II (Zjchi2). Zjchi1 and, Zjchi2 expression was high in root and stolen and was induced in seedlings by Rhizoctonia solnai AG2-2 (IV) infection. To assess their antifungal activity, the two chitinases were overexpressed in Escherichia coli and purified using Ni2+ and glutathione affinity column chromatography. The purified recombinant chitinases showed broad-spectrum antifungal activity against Rhizoctonia solnai AG2-2 (IV), Rhizoctonia solnai AG-1 (IA), Rhizoctonia cerealis, Botrytis cinerea, Fusarium culmorum, Fusarium graminearum and Trichoderma reesei.