REPORT FROM PATHOLOGY COMMITTEE - ISSCT

1 REPORT FROM PATHOLOGY COMMITTEE Roger Bailey INTRODUCTION The 1995-98 inter-congress period has been an active, interesting and productive one for the PATHOLOGY section. Thre were three meetings at which international sugarcane pathologists met, the highlight being the 5th ISSCT PATHOLOGY Workshop, combined with Molecular Biology, held in South Africa in May 1997,There were also workshops on RSD in Edinburgh and yellow leaf syndrome at Rothamsted in August 1998. Sectional COMMITTEE members for the period were: Roger Bailey (Sough Africa) Chairman, Jack Comstock (USA) Barry Croft (Australia), Philippe Rott (France), Salem Saumtally (Mauritius).

2 The sectional COMMITTEE met on two occasions, in May 1997 and August 1998, and the members were in frequent contact on a range of issues. The new book A Guide to Sugarcane Diseases, the production of which is coordinated by CIRAD, is now in an advanced stage of preparation. Research progress on yellow leafissyndrome (YLS) is being made and there were several reports of new diseases and reports of outhreaks of well-known diseases in new areas. 5th PATHOLOGY & 2nd Molecular Biology combined Workshop The Workshop was held in South Africa from 12-12 May 1997 and was attended by 62 delegates.

3 These included 47 from outside South Africa and most of the world's leading sugarcane researchers in the two disciplines. Seventeen countries were represented. The excellent attendance contributed greatly to the success of the meeting. A total of 42 verbal and 22 poster presentations were made under six session topics. Most of the technical and discussion sessions were held as joint meetings. This was beneficial because of the important role of molecular biology in sugarcane PATHOLOGY research and because PATHOLOGY topics constitute one of the most important research areas in molecular biology.

4 There was also valuable input from SASEX breeders on matters such as marker aided selection. The joint meetings and the provision of ample time for discussions were important contributory factors to the success of the workshop. Session topics and contributions were: Yellow Leaf Syndrome: 10 papers, 2 posters Genetic Engineering: 8 papers, 6 posters Molecular Biological Studies on Pathogens: 8 papers, 6 posters Ratoon Stunting Disease: 6 Papers, 4 posters Genetic Markers: 4 papers, 2 posters General Sugarcane PATHOLOGY : 6 papers, 2 posters Three invited speakers established a high scientific standard for the workshop: Dr Anna Tymon (IACA-Rothamsted, UK) - Phytoplasmas: detection, diagnosis and classij?

5 Cation. I Dr. Robert Birch (University of Queensland, Australia) - Progress and technical liltlitations to practical application of transgenic:,sugarcane. Dr. Jean-Christophe Glaszn~ann (CIRAD, Montpellier, France) - Molecular nzarkers for sugarcane genetics. Delegates visited the SASEX facilities at Mount Edgecombe on 14 May and were addressed on the South African sugar industry and the disease situation in the industry. A highlight of the visit was the demonstration by Dr. Pieter Cronje of his work on YLS phytoplasmas. A post-workshop tour of northern KwaZulu-Natal was attended by 39 delegates.

6 It included visits to the SASEX field station at pongola and disease aspects of commercial sugar interests, as well as tourist attractions. The delegates to the workshop agreed that joint workshops in which related disciplines combine to lnutual advantage have much to offer. The interaction between PATHOLOGY and Molecular Biology is particularly strong, as is the link between both these disciplines and Breeding. RSD Workshop, Edinburgh, August 1998 The 7th International Congress of Plant PATHOLOGY (ICPP98) was held in Edinburgh from 9-14 August 1998. There was much information of relevance to sugarcane PATHOLOGY , particularly in diagnostics and there were a number of posters on sugarcane diseases.

7 The congress included a Workshop on Ratoon Stunting Disease of Sugarcane, organised by Dr. Stevens Brumbley of BSES. This had some 35 participants, including inany sugarcane pathologists. Topics in the RSD workshop included overviews of RSD and siinilar pathogens, n~olecular approaches to RSD research, diagnostic procedures, screening for resistance and the economic impact of RSD on sugar industries. Items of interest included: Progress in the USA in selecting for RSD resistance. Information from Australia that phase contrast microscopy and the serology-based EB-EIA method of diagnosis are similar in sensitivity.

8 Standard and real-time PCR offer a much higher order of sensitivity for detecting , usef~~l for research but of limited use for practical control of RSD. Apart from South Africa, losses from RSD in sugar industries in southern and central Africa range from 5% to more than 20% of producti8n. Longer breaks between stubble destruction and replanting are necessary to achieve better control. An initiative from BSES was developed to seek support for C. xyli subsp xyli to be included in a project on sequencing the genomes of important pathogens. I Yellow leaf syndrome workshop, Rothamsted, August 1998 A scientific workshop on YLS, organised by Pihil Jones, was held at Rothamsted from 16-18 August and was attended by 17 sugarcane pathologists from 12 countries.

9 These' included the majority of workers currently involved in research on YLS. The latest findings on the sugarcane yellows pl~ytoplastna (ScYP), the sugarcane yellow leaf virus (ScYLV), and the attitudes of various sugar industries to YLS were discussed. Dr. Pieter Cronje of SASEX rzported the detection of two phytoplasmas, ScYP I and 11, that he has found to be associated with YLS and the international distribution of these. A laboratory manual for identifying YLS phytoplasmas, prepared by Dr. Conje, was distributed. This should facilitate progress by other workers into the cause of YLS.

10 Good progress has been made in characterising the luteovin~s ScYLV and determining its distribution. ScYLV is very common in a number of sugar industries, although rare in Africa, and no good evidence for an association between ScYLV and YLS symptoms was presented. The attitudes of most sugar industries to the introduction of foreign varieties infected by ScYP or ScYLV are essentially conservative. This is mainly due to the lack of knowledge of variation in these pathogens and on their economic significance and control measures. A REPORT on this workshop is available New Book The new book A guide to Sugarcane Diseases,the production of whicl~ is being coordinated by Dr.