Colonization of the vegetative stage of rice plants by the false smut fungus <i>Villosiclava virens,</i> as revealed by a combination of species‐specific detection methods

Tanaka, Eiji; Kumagawa, Tsuyoshi; Ito, N.; Nakanishi, A.; Ohta, Yasuo; Suzuki, Eijiro; Adachi, Naoto; Hamada, A.; Ashizawa, Taketo; Ohara, Toshiaki; Tsuda, Mitsuya

doi:10.1111/ppa.12540

Cited by 24 publications

(9 citation statements)

References 20 publications

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“…The pathogens could not penetrate the sclerenchyma cell or the endothelial cells of the root, so they could not reach the endodermis, the phloem of the rice root, and could not expand into the stem tissue. This is different from previous reports in which the pathogen grew along the sieve tube of the rice (Ikegami ; Tanaka et al, ). Fan et al reported that U. virens displayed epiphytic characteristics on abiotic and biotic surfaces in the presence of water (Fan et al, ).…”

Section: Resultscontrasting

confidence: 99%

Cytological studies on the infection of rice root by Ustilaginoidea virens

Yong

Liu

Chen

et al. 2018

Microscopy Res & Technique

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In recent years, false smut disease of rice has been one of the most important diseases of cultivated rice in China. Ustilaginoidea virens is an ascomycete fungal pathogen that causes false smut in rice. There is always controversy about whether the pathogen can infect the rice root and cause the occurrence of false smut, mainly due to lack direct cytological evidence. In our study, we observed the cytological structure of rice root invaded by U. virens. The results showed that U. virens could attach to the surface of young roots and penetrate into the intercellular space of the root epidermis. The cellulose microfibrils in root epidermal cell wall are very loose and soft, and their structural features are similar to filaments of rice. After the fungus infected the roots, a large number of fungal secretions were accumulated outside of the cell walls. At 40 days, the fungus began to degrade, but pathogens still had not infected the sclerenchyma, in which the cells are arranged densely and the cell walls are thicker. U. virens could not cross the sclerenchyma layer into the endodermis and phloem of the root. To some extent, the U. virens infection affected the leaf and root growth of the rice. After inoculation, there was no fungal mycelium found in transverse sections of the rice young stem. These results suggested that root colonization of U. virens does not lead to systemic invasion in rice.

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Section: Resultscontrasting

confidence: 99%

Cytological studies on the infection of rice root by Ustilaginoidea virens

Yong

Liu

Chen

et al. 2018

Microscopy Res & Technique

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“…After the transplanting of rice in paddy fields, chlamydospores attach to the roots and then germinate, with the resulting hyphae invading the intercellular space of the roots (Prakobsub & Ashizawa, 2017). Finally, the hyphae extend toward the tiller buds at the basal portion of the juvenile leaf sheath (Tanaka et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Effect of calcined lime (CaO) on chlamydospores of the rice false smut pathogen, Villosiclava virens, and their root attachment and infection

2021

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Rice false smut caused by Villosiclava virens is a devastating disease. The smut balls contain chlamydospores, which fall onto paddy soils to become the primary inoculum. After transplanting, the chlamydospores subsequently germinate and infect rice roots. The application of a CaO‐containing fertilizer to paddy soils can inhibit the development of rice false smut disease; however, the underlying mechanism is unknown. In this study, we evaluated the suppression of chlamydospore behaviour due to CaO. Specifically, we clarified the effects of the following on chlamydospore morphology and germination: (a) pH, (b) calcium (Ca) concentration, (c) Ca concentration (pH adjusted to 6.5), and (d) CaO‐added soil solution. Germination was suppressed at pH 4 and 10, in contrast with the normal germination at pH 6, 7, and 8. Treatments with more than 10 mg/L Ca melted the outer layer of chlamydospores and suppressed germination regardless of whether the pH was adjusted to 6.5. A saturated CaO solution induced bursting of chlamydospores. Suppressed germination and a melted outer chlamydospore layer were also observed, even though the soil buffering effect initially prevented the CaO‐mediated pH increase. Furthermore, the chlamydospores within 15 mm from the CaO small lump exhibited suppressed germination in soil. In addition, there was no effect of CaO treatment on chlamydospore attachment to rice roots and hyphal invasion of rice roots in in vitro inoculation tests. These results suggest that Ca concentration is an important factor for inhibiting the occurrence of rice false smut disease.

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“…The observation of Chou (1967) showed 26-28°C as a suitable temperature for rice false smut. In the very recent findings, Tanaka et al (2017) revealed that while the pathogen was present in rice plants, the development of the disease depended on meteorological conditions, where under field conditions no infection occurred at average temperature of 28°C and good infection was found at 25°C. The findings of Tanaka et al (2017) clearly support the approach of this study on designating temperature during the smut ball formation period as the key indicator for expressing the disease on a crop.…”

Section: Discussionmentioning

confidence: 99%

Weather Condition, Seasonal Variation and Ball Development Pattern in Relation to Rice False Smut Disease in Bangladesh

Nessa

Salam²,

Haque

et al. 2019

Bangladesh Rice J.

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Rice false smut (RFSm) is an international disease. The effect of the disease has become seriously evident in Bangladesh since 2010. The disease is predominant in the country in the ‘T. Aman’ rice growing season. Its occurrence in other rice growing seasons not well studied and recorded. Information on driving weather variable(s) causing the disease epidemic is scanty and not ground-truthed. This study, conducted in the experimental farm of the Bangladesh Rice Research Institute, Gazipur, Bangladesh, attempted to fill those information gaps. The association of disease incidence and weather parameters such as relative humidity, cloud hour and rainfall, was inconsistence except for the daily average temperature. High disease incidence occurred when the average temperature during panicle emergence period ranged between 22-27°C; any temperature below or above the range linearly decreased the disease incidence. RFSm disease was recorded in the study area in all the months, except for in February and March. The distribution in the incidence of disease in the three rice growing seasons followed the order of ‘T. Aman’ > ‘Aus’ > ‘Boro’; it was ~ six times less in ‘Aus’ and ~ eight times less in ‘Boro’ season, compared to ‘T. Aman’ season. New balls formed on infected panicles in batch by batch. High number of such batches formed in ‘T. Aman’ season. The final status of the disease in an infected crop was the accumulation of incidence of the disease in each batch. This study provided key epidemiology on the development of RFSm in nature and it is concluded such information on the disease under local conditions would be the key to designing management options. Bangladesh Rice j. 2018, 22(1): 57-64

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Colonization of the vegetative stage of rice plants by the false smut fungus Villosiclava virens, as revealed by a combination of species‐specific detection methods

Cited by 24 publications

References 20 publications

Cytological studies on the infection of rice root by Ustilaginoidea virens

Cytological studies on the infection of rice root by Ustilaginoidea virens

Effect of calcined lime (CaO) on chlamydospores of the rice false smut pathogen, Villosiclava virens, and their root attachment and infection

Weather Condition, Seasonal Variation and Ball Development Pattern in Relation to Rice False Smut Disease in Bangladesh

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