Reprogramming of the wheat transcriptome in response to infection with Claviceps purpurea, the causal agent of ergot

Abstract

Background Ergot, caused by the fungal pathogen Claviceps purpurea, infects the female flowers of a range of cereal crops, including wheat. To understand the interaction between C. purpurea and hexaploid wheat we undertook an extensive examination of the reprogramming of the wheat transcriptome in response to C. purpurea infection through floral tissues (i.e. the stigma, transmitting and base ovule tissues of the ovary) and over time. Results C. purpurea hyphae were observed to have grown into and down the stigma at 24 h (H) after inoculation. By 48H hyphae had grown through the transmitting tissue into the base, while by 72H hyphae had surrounded the ovule. By 5 days (D) the ovule had been replaced by fungal tissue. Differential gene expression was first observed at 1H in the stigma tissue. Many of the wheat genes differentially transcribed in response to C. purpurea infection were associated with plant hormones and included the ethylene (ET), auxin, cytokinin, gibberellic acid (GA), salicylic acid and jasmonic acid (JA) biosynthetic and signaling pathways. Hormone-associated genes were first detected in the stigma and base tissues at 24H, but not in the transmitting tissue. Genes associated with GA and JA pathways were seen in the stigma at 24H, while JA and ET-associated genes were identified in the base at 24H. In addition, several defence-related genes were differential expressed in response to C. purpurea infection, including antifungal proteins, endocytosis/exocytosis-related proteins, NBS-LRR class proteins, genes involved in programmed cell death, receptor protein kinases and transcription factors. Of particular interest was the identification of differential expression of wheat genes in the base tissue well before the appearance of fungal hyphae, suggesting that a mobile signal, either pathogen or plant-derived, is delivered to the base prior to colonisation. Conclusions Multiple host hormone biosynthesis and signalling pathways were significantly perturbed from an early stage in the wheat – C. purpurea interaction. Differential gene expression at the base of the ovary, ahead of arrival of the pathogen, indicated the potential presence of a long-distance signal modifying host gene expression.

Effective Pollen-Fertility Restoration Is the Basis of Hybrid Rye Production and Ergot Mitigation

“…It was previously taken for granted that ergot infection does not cause any defense reactions in rye. However, recent transcriptomic studies showed that in both wheat and rye, the host plant responds to the infection by upregulating defense-related genes, precisely when the germ tube reaches the ovary [73,74]. Thus, the host obviously recognizes the Claviceps infection.…”

ERGOT Claviceps purpurea (Fries) Tulasne ALKALOID DIVERSITY AND VIRULENCE: EVOLUTION, GENETIC DIVERSIFICATION, AND METABOLIC ENGINEERING (review)

“…Как уже отмечалось, эргоалкалоиды сыграли существенную роль в распространении спорыньи и расширении ареала этого аскомицета. C. purpurea пора-жает ряд экономически значимых зерновых культур, в том числе рожь, пшеницу и ячмень (19,49,147). Спорынья инфицирует злаки во время цветения, заражая ткани неоплодотворенных соцветий женских растений и заменяя семена склероциями (53,147).…”

“…Спорынья инфицирует злаки во время цветения, заражая ткани неоплодотворенных соцветий женских растений и заменяя семена склероциями (53,147). Таким образом, перекрестноопыляющиеся злаки, которые демонстрируют открытое цветение, такие как рожь, особенно подвержены риску заражения (49,148). Спорынья инфекционна и для гибридных форм ячменя или пшеницы, получивших чувствительность как побочный результат селекции (49,149,150).…”

“…Таким образом, перекрестноопыляющиеся злаки, которые демонстрируют открытое цветение, такие как рожь, особенно подвержены риску заражения (49,148). Спорынья инфекционна и для гибридных форм ячменя или пшеницы, получивших чувствительность как побочный результат селекции (49,149,150). Инфекции C. purpurea подвержены гексаплоидная мягкая пшеница (Triticum aestivum L.) и тетраплоидная твердая пшеница T. turgidum subsp.…”

“…Для анализа генома спорыньи применяют пиросеквенирование методом одно-или парноконцевых прочтений (single/paired-end pyrosequencing) (42), секвенирование с парноконцевыми прочтениями (paired-end sequencing, PEs) (43,44), секвенирование по Сэнгеру (Sanger sequencing) (45), пиросеквенирование методом дробовика (shotgun pyrosequencing) и секвенирование спаренных концов (matepair sequencing) (46). Так, PEs применяли для анализа транскриптома при сигнальных взаимодействиях C. purpurea с хозяином Secale cereale (47) и секвенирования генома Claviceps paspali (48), мультиплексное секвенирование с одноконцевыми прочтениями (single-end multiplexed sequencing) -для анализа транскриптома пшеницы при заражении C. purpurea (49).…”