Symptoms, host range, taxonomy and life cycle of sarocladium

PAT 201

1. COURSE TEACHER Dr. PARTHASARATHY S Asst. Professor (Plant Pathology) STUDENT K.K. SUJAYBRAHATHEESH ID. NO. 2017021075 COLLEGE OF AGRICULTURAL TECHNOLOGY (Affiliated to Tamil Nadu Agricultural University, Coimbatore-3) Kullapuram (Po), ViaVaigai Dam, Theni-625 562 SYMPTOMS, HOST RANGE, TAXONOMY AND LIFE CYCLE OF SAROCLADIUM

2. SAROCLADIUM   Sarocladium  presently encompasses 10 species.  Sarocladium oryzae , the type species of the genus, is an important plant pathogen causing sheath-rot of rice ( Oryza sativa ). It is also known to produce antimicrobial secondary metabolites , such as helvolic acid and cerulenin .

3. TAXONOMY Domain : Eukaryota      Kingdom : Fungi          Phylum : Ascomycota              Subphylum : Pezizomycotina                  Class : Sordariomycetes                     Subclass : Hypocreomycetidae                          Order : Hypocreales                              Genus : Sarocladium                                  Species : S . oryzae

4. SAROCLADIUM   ORYZAE Sarocladium oryzae  (Sawada) is a plant pathogen causing the sheath rot disease of rice. In culture it produces 0.3 0.627  micrograms of  helvolic acid and 0.9-4.8 micrograms of  cerulenin  per milliliter of culture medium. The level of helvolic acid correlated with a higher incidence of sheath rot disease.

5. SAROCLADIUM   ORYZAE Rice grains from infected plants were found to contain 2.2 micrograms helvolic acid and 1.75 micrograms of cerulein per gram of infected seeds, which induce  chlorosis  and reduce the seed viability and seedling health. S. oryzae  has also been known as  Acrocylindrium oryzae   (Sawada).

6. SYMPTOMS Discoloration in the flag leaf sheath

7. SYMPTOMS Rotting occurs on the leaf sheath that encloses the young panicles. Irregular spots or lesions , with dark reddish brown margins and gray center .

8. SYMPTOMS Severe infection causes entire or parts of young panicles to remain within the sheath

9. SYMPTOMS Lesions enlarge and often coalesce and may cover the entire leaf sheath. Unemerged panicles rot and florets turn red-brown to dark brown. Whitish powdery growth inside the affected sheaths and young panicles.

10. SYMPTOMS Infected panicles and  grains are sterile , shriveled, partially or unfilled, and discolored. The disease is important during the heading towards the maturity stages of the rice crop.

11. SYMPTOMS

12. SYMPTOMS

13. SYMPTOMS

14. HOST RANGE The Host Range of this pathogen has not been studied. Few reports are only avaliable Balakrishnan and Nair (1981) reported that field weeds Cyperus diformis , Echinocholoa crusgalli , Monochoria vaginalis and Cyperus teneriffe were naturally infected hosts of S. oryzae . Echinocholoa colona , was also found to play a role as an alterate host for this pathogen

15. LIFE CYCLE

16. LIFE CYCLE The fungus produces white mycelium, sparsely branched , septate , and measures 1.5-2mm in diameter. Conidiophores arising from the mycelium are slightly thicker than the vegetative hyphae , branched once or twice, each time with 3-4 branches in a whorl.

17. LIFE CYCLE The fungus invades rice through the plant's stomata and wounds and grows intercellularly in the vascular bundles and mesophyll tissues.

18. REFERENCES Alice D, Jeyalakshmi C, Krishnamoorthy A.S and Karthikeyan M, 2017. Fundamentals of Phyto Pathology. Sri Sakthi Promotional Litho Process, Coimbatore. https://www.cabi.org/isc/datasheet/48393 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4510268/ https://en.wikipedia.org/wiki/Sarocladium_oryzae http://www.agritech.tnau.ac.in/expert_system/paddy/cpdissrsb.html http://krishikosh.egranth.ac.in/handle/1/89295