Manipulating rainfall to study symptom expression of <i>Botrytis cinerea</i> infection in wine grapes
Authors: Hill G.N. , Henshall W.R. , Beresford R.M. 
Published: March 2018

Botrytis cinerea infection of wine grapes can result in a variety of symptoms. The most common symptom is botrytis bunch rot (BBR), where infected berries rot and shrivel, and eventually produce fungal sporulation. Another symptom is slip skin, where the skins of infected ripe berries slide easily from the pulp. It is hypothesised that a reduction in osmotic potential in grape berries due to late-season rainfall leads to slip skin symptom development. Hyphal growth of B. cinerea on osmotically adjusted agar was inhibited at osmotic potentials associated with near-ripe berries. Vine sheltering was used in a research vineyard to manipulate rainfall artificially and to alter berry sugar content in Vitis vinifera Sauvignon blanc vines, with the aim of increasing osmotic potential and altering symptom expression. Both BBR and slip skin symptoms were affected by the various sheltering conditions, with sheltered vines having lower BBR and higher slip skin at harvest.
REFERENCES
Becker T, Grimm E, Knoche M 2012. Substantial water uptake into detached grape berries occurs through the stem surface. Australian Journal of Grape and Wine Research 18: 109-114. https://doi.org/10.1111/j.1755-0238.2011.00177.x
Beever RE, Laracy EP 1986. Osmotic adjustment in the filamentous fungus Aspergillus nidulans. Journal of Bacteriology 168: 1358-1365. https://doi.org/10.1128/jb.168.3.1358-1365.1986
Beresford RM, Hill GN 2008. Botrytis control without fungicide residues - is it just a load of rot? New Zealand Winegrower 12: 104-106.
Beresford RM, Evans KJ, Wood PN, Mundy DC 2006. Disease assessment and epidemic monitoring methodology for bunch rot (Botrytis cinerea) in grapevines. New Zealand Plant Protection 59: 355-360.
Bondada BR, Matthews MA, Shackel KA 2005. Functional xylem in the post-vÃ©raison grape berry. Journal of Experimental Botany 56: 2949-2957. https://doi.org/10.1093/jxb/eri291
Choat B, Gambetta GA, Shackel KA, Matthews MA 2009. Vascular function in grape berries across development and its relevance to apparent hydraulic isolation. Plant Physiology 151: 1677-1687. https://doi.org/10.1104/pp.109.143172
Clarke SJ, Hardie WJ, Rogiers SY 2010. Changes in susceptibility of grape berries to splitting are related to impaired osmotic water uptake associated with losses in cell vitality. Australian Journal of Grape and Wine Research 16: 469-476. https://doi.org/10.1111/j.1755-0238.2010.00108.x
Diakou P, Moing A, Svanella L, Ollat N, Rolin DB, Gaudillere M, Gaudillere JP 1997. Biochemical comparison of two grape varieties differing in juice acidity. Australian Journal of Grape and Wine Research 3: 1-10. https://doi.org/10.1111/j.1755-0238.1997.tb00122.x
Grolemund G, Wickham H 2011. Dates and times made easy with lubridate. 2011 40: 25.
Harris RF 1981. Effect of water potential on microbial growth and activity. In: Parr JF, Gardner WR, Elliott LF eds. Water Potential Relations in Soil Microbiology. SSSA Special Publication. Soil Science Society of America. Pp. 23-95.
Hill GN, Beresford RM, Evans KJ 2010. Tools for accurate assessment of botrytis bunch rot (Botrytis cinerea) on wine grapes. New Zealand Plant Protection 63: 174-181.
Hill GN, Evans KJ, Beresford RM 2014a. Use of nitrate non-utilising (nit) mutants to determine phenological stages at which Botrytis cinerea infects wine grapes causing botrytis bunch rot. Plant Pathology 63: 1316-1325. https://doi.org/10.1111/ppa.12225
Hill GN, Evans KJ, Beresford RM, Dambergs RG 2014b. Comparison of methods for the quantification of botrytis bunch rot in white wine grapes. Australian Journal of Grape and Wine Research 20: 432—441. https://doi.org/10.1111/ajgw.12101
Keller M, Smith JP, Bondada BR 2006. Ripening grape berries remain hydraulically connected to the shoot. Journal of Experimental Botany 57: 2577-2587. https://doi.org/10.1093/jxb/erl020
Loschiavo A, Scholefield P, Morrison J, Ferris M 2010. The cost of pests and diseases to the Australian winegrape industry. Australian Viticulture 14: 15-19.
McCarthy MG, Coombe BG 1999. Is weight loss in ripening grape berries cv. Shiraz caused by impeded phloem transport? Australian Journal of Grape and Wine Research 5: 17-21. https://doi.org/10.1111/j.1755-0238.1999.tb00146.x
Mendiburu Fd 2016. agricolae: Statistical Procedures for Agricultural Research. https://CRAN.R-project.org/package=agricolae.
Mundy DC, Beresford RM 2007. Susceptibility of grapes to Botrytis cinerea in relation to berry nitrogen and sugar concentration. New Zealand Plant Protection 60: 123-127.
Nelson KE 1956. The effect of Botrytis infection on the tissue of Tokay grapes. Phytopathology 46: 223-229.
NIWA 2017. Mean monthly rainfall (mm). https://www.niwa.co.nz/education-and-training/schools/resources/climate/meanrain (05-05-2017).
Pezet R, Viret O, Perret C, Tabacchi R 2003. Latency of Botrytis cinerea Pers.: Fr. and biochemical studies during growth and ripening of two grape berry cultivars, respectively susceptible and resistant to grey mould. Journal of Phytopathology 151: 208-214. https://doi.org/10.1046/j.1439-0434.2003.00707.x
R Core Team 2016. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/.
R Studio Team 2016. RStudio: Integrated Development for R. RStudio, Inc., Boston, MA. http://www.rstudio.com/.
Rogiers SY, Smith JA, White R, Keller M, Holzapfel BP, Virgona JM 2001. Vascular function in berries of Vitis vinifera (L) cv. Shiraz. Australian Journal of Grape and Wine Research 7: 47-51. https://doi.org/10.1111/j.1755-0238.2001.tb00193.x
Schindelin J, Arganda-Carreras I, Frise E, Kaynig V, Longair M, Pietzsch T, Preibisch S, Rueden C, Saalfeld S, Schmid B, Tinevez J-Y, White DJ, Hartenstein V, Eliceiri K, Tomancak P, Cardona A 2012. Fiji: an open-source platform for biological-image analysis. Nature Methods 9: 676-682. https://doi.org/10.1038/nmeth.2019
Smart R, Robinson M 1991. Sunlight into Wine. Winetitles, Adelaide, Australia.
Taiz L, Zeiger E 1998. Plant Physiology. Sinauer Associates, Sunderland, MA, USA.
Tyerman SD, Tilbrook J, Pardo C, Kotula L, Sullivan W, Steudle E 2004. Direct measurement of hydraulic properties in developing berries of Vitis vinifera L. cv Shiraz and Chardonnay. Australian Journal of Grape and Wine Research 10: 170-181. https://doi.org/10.1111/j.1755-0238.2004.tb00020.x
Whiting EC, Rizzo DM 1999. Effect of water potential on radial colony growth of Armillaria mellea and A. gallica isolates in culture. Mycologia 91: 627-635. https://doi.org/10.2307/3761248
Wickham H 2009. ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York.
Wickham H 2016. tidyverse: Easily Install and Load 'Tidyverse' Packages. https://CRAN.R-project.org/package=tidyverse.
Wickham H, Bryan J 2017. readxl: Read Excel Files. https://CRAN.R-project.org/package=readxl.
Wilcox WF, Gubler WD, Uyemoto JK 2015. Compendium of Grape Diseases, Disorders, and Pests: Second Edition. APS Press, St Paul, MN, USA.