• Journal of Plant Biology
• /
• v.28 no.4
• /
• pp.261-270
• /
• 1985

The portion of Cuscuta japonica haustorium which lies external to the host tissues, the upper haustorium, was investigated at the light- and electron-microscopic levels. The haustorium lightly contacted with the host was formed by the expansion of the epidermis and cortex of the stem at the contact side, and to have a group of meristematic cells within the haustorial cortex. When such a haustorium was closely contacted with the host, the meristematic region transformed into a primordial structure of the endophyte (endophyte primordium, EP) which may penetrate into the host tissues. EP consisted of the three kinds of cell group: dividing cells at the adaxial or proximal side; large, elongate cells (idioblasts) at the middle portion,; compressed cells at the abaxial or basal side. the idioblasts were characterized by the presence of large nucleus, dense cytoplasm, several small vacuoles, and abundant cell organelles including the multilamellar structures and cytosegresomes, and thus suggested to have a high metabolic activity. The features of the EP were discussed in relation to the possibility of the penetrating into host tissues.

• Korean Journal of Plant Taxonomy
• /
• v.43 no.4
• /
• pp.252-262
• /
• 2013

During the floristic survey on Phnom Bokor National Park, Kampot, Cambodia, we encountered Balanophora fungosa var. indica, which is a tropical holoparasitic plant. To identify its host species, we collected host roots and trees nearby and tried to identify them using DNA barcoding approach. We applied plastid rbcL and matK gene regions as DNA barcode markers, and successfully amplified and sequenced the markers from 15 host roots and seven tree samples. Obtained host root sequences were identified as Primulaceae, Celastraceae, Myrtaceae, and Oleaceae, while trees nearby are Oleaceae, Myrtaceae, Sapindaceae, Rosaceae, Clusiaceae, Ericaceae, and Lauraceae. At genus level, host species are identified as Myrsine, Euonymus, Syzygium, and Olea, but failed in species discrimination. Myrsine (Primulaceae) and Olea (Oleaceae) are reported here as host species of B. fungosa var. indica for the first time. Further sampling and comparative work, and DNA barcoding will help recognize the biodiversity of the area and host species of Balanophora, together with their evolution.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.71.1-71
• /
• 2003

Most major plant pathogenic bacteria in Korea belong to Xanthomonas spp.. Xanthomonas oryzae pv. oryzae is a major pathogen in rice, X. campestris pv. vesicatoria in pepper, X. axonopodis pv. giycines in soybean, X. campestris pv. campestris in cabbage, and X. axonoposid pv. citri in tangerin. Host specificity of the bacterial pathogen depends on the avirulence gene in the pathogen and the corresponding resistance gene in host plants. Many avirulence genes in bacteiral pathogen located on the native plasmids. However, the presence of the native plasmids in Xanthomonas spp. was not investigated well. In order to study the host specificity, we isolated native plasmids from Xanthomonas spp. and compared those plasmids each other, The presence of the native plasmids and the characteristics of the plasmids depended on the bacterial strains. In the X. axonopodis pv. glycines, most strains carried native plasmids but some strains did not. Some strains carry about 60 kb native plasmids including 3 different aviurlence genes. We will discuss the characteristics of the native plasmids isolated from the Xanthomonas spp.

• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.97-107
• /
• 2015

Alteration of genetic make-up of the isolates and mono-sporidial strains of Tilletia indica causing Karnal bunt (KB) disease in wheat was analyzed using DNA markers and SDS-PAGE. The generation of new variation with different growth characteristics is not a generalized feature and is not only dependant on the original genetic make up of the base isolate/monosporidial strains but also on interaction with host. Host determinant(s) plays a significant role in the generation of variability and the effect is much pronounced in monosporidial strains with narrow genetic base as compared to broad genetic base. The most plausible explanation of genetic variation in presence of host determinant(s) are the recombination of genetic material from two different mycelial/sporidia through sexual mating as well as through parasexual means. The morphological and development dependent variability further suggests that the variation in T. indica strains predominantly derived through the genetic rearrangements.

• The Plant Pathology Journal
• /
• v.23 no.4
• /
• pp.281-286
• /
• 2007

Interactions between viral proteins and host proteins are essential for virus replication. Especially, translation of viral genes completely depends on the host machinery. In potyviruses, interactions of genome-linked viral protein (VPg) with host translation factors including eIF4E, eIF(iso)4E, and poly(A)-binding protein (PABP) has previously been characterized. In this study, we investigated interactions between Soybean mosaic virus (SMV) viral proteins and host translation factors by yeast two-hybrid system. SMV VPg interacted with eIF4E, eIF(iso)4E, and PABP in yeast two-hybrid system, while SMV helper component proteinase (HC-pro) interacted with neither of those proteins. The interaction between SMV NIb and PABP was also detected. These results are consistent with those reported previously in other potyviruses. Interestingly, we found reproducible and specific interactions between SMV coat protein (CP) and PABP. Deletion analysis showed that the region of CP comprising amino acids 116 to 206 and the region of PABP comprising amino acids 520 to 580 are involved in CP/PABP interactions. Soybean library screening with SMV NIb by yeast two-hybrid assay also identified several soybean proteins including chlorophyll a/b binding preprotein, photo-system I-N subunit, ribulose 1,5-biphosphate carboxylase, ST-LSI protein, translation initiation factor 1, TIR-NBS type R protein, RNA binding protein, ubiquitin, and LRR protein kinase. Altogether, these results suggest that potyviral replicase may comprise a multi-protein complex with PABP, CP, and other host factors.

• The Plant Pathology Journal
• /
• v.18 no.2
• /
• pp.63-67
• /
• 2002

To understand plant-pathogen interactions, a complete set of hot pepper genes differentially expressed against pathogen attack was isolated. As an initial step, hundreds of differentially expressed cDNAS were isolated from hot pepper leaves showing non-host resistance against bacterial plant pathogens (Xanthomonas campestris pv. glycines and Pseudomonas syringae pv. syringae) using differential display reverse transcription polymerase chain reaction (DDDRT-PCR) technique. Reverse Northern and Northern blot analyses revealed that 50% of those genes were differentially expressed in pepper loaves during non-host resistance response. Among them, independent genes without redundancy were micro-arrayed for further analysis. Random EST sequence database were also generated from various CDNA libraries including pepper tissue specific libraries and leaves showing non-host hypersensitive response against X. campestris pv. glycines. As a primary stage, thousands of cDNA clones were sequenced and EST data were analyzed. These clones are being spotted on glass slide to study the expression profiling. Results of this study may further broaden knowledge on plant-pathogen interactions.

• The Plant Pathology Journal
• /
• v.33 no.3
• /
• pp.213-228
• /
• 2017

Plasmodesmata (PDs) are specialized intercellular channels that facilitate the exchange of various molecules, including sugars, ribonucleoprotein complexes, transcription factors, and mRNA. Their diameters, estimated to be 2.5 nm in the neck region, are too small to transfer viruses or viral genomes. Tobacco mosaic virus and Potexviruses are the most extensively studied viruses. In viruses, the movement protein (MP) is responsible for the PD gating that allows the intercellular movement of viral genomes. Various host factors interact with MP to regulate complicated mechanisms related to PD gating. Virus replication and assembly occur in viral replication complex (VRC) with membrane association, especially in the endoplasmic reticulum. VRC have a highly organized structure and are highly regulated by interactions among the various host factors, proteins encoded by the viral genome, and the viral genome. Virus trafficking requires host machineries, such as the cytoskeleton and the secretory systems. MP facilitates the virus replication and movement process. Despite the current level of understanding of virus movement, there are still many unknown and complex interactions between virus replication and virus movement. While numerous studies have been conducted to understand plant viruses with regards to cell-to-cell movement and replication, there are still many knowledge gaps. To study these interactions, adequate research tools must be used such as molecular, and biochemical techniques. Without such tools, virologists will not be able to gain an accurate or detailed understanding of the virus infection process.

• The Plant Pathology Journal
• /
• v.27 no.2
• /
• pp.128-137
• /
• 2011

Fifty two Macrophomina phaseolina isolates were recovered from 24 host plant species through the 14 Iranian provinces. All isolates were confirmed to species using species-specific primers. The colony characteristics of each isolate were recorded, including chlorate phenotype, relative growth rate at $30^{\circ}C$ and $37^{\circ}C$, average size of microsclerotia, and time to microsclerotia formation. The feathery colony phenotype was the most common (63.7%) on the chlorate selective medium and represented the chlorate sensitive phenotype of the Iranian Macrophomina phaseolina population. Meantime, inter simple sequence repeats (ISSR) Markers were used to assess the genetic diversity of the fungus. Unweighted pair-group method using arithmetic means (UPGMA) clustering of data showed that isolates did not clearly differentiate to the specific group according to the host or geographical origins, however, usually the isolates from the same host or the same geographic origin tend to group nearly. Our results did not show a correlation between the genetic diversity based on the ISSR and phenotypic characteristics. Similar to the M. phaseolina populations in the other countries, the Iranian isolates were highly diverse based on the phenotypic and the genotypic characteristics investigated and needs more studies using neutral molecular tools to get a deeper insight into this complex species.

• The Plant Pathology Journal
• /
• v.16 no.2
• /
• pp.79-82
• /
• 2000

No Abstract.See Full-text

• The Plant Pathology Journal
• /
• v.15 no.2
• /
• pp.99-104
• /
• 1999