Penyakit Tanaman Bagaimana Dapat Mempengaruhi Ketahanan Pangan dan

Penyakit Tanaman: Bagaimana Dapat Mempengaruhi Ketahanan Pangan dan Bagaimana Dipengaruhi Perubahan Antropogoni Oleh Irda Safni

Secara umum, sekitar 16% tanaman kehilangan hasil akibat penyakit tanaman setiap tahunnya. Tetapi kehilangan hasil dapat lebih tinggi lagi ketika : • Patogen baru diintroduksi • Kondisi cuaca yang optimal • Tanaman ditanam secara skala besar monokultur Tanaman inang yang rentan Penyak it Lingkungan yang kondusif Patogen yang virulen

Manusia dapat menyebabkan: • Transportasi tanaman dan mikroba yang lebih sering • Perubahan iklim (meningkatnya suhu & curah hujan) • Perluasan pertanian dalam skala industri

Beberapa Tanaman Berdampak Epidemik Tinggi Stem rust of wheat: Biblical times – present (widely planted crop, mobile and rapidly evolving pathogen; big concern about aggressive new race Ug 99) Irish potato famine: 1846 -48 (widely planted genetically uniform crop, pathogen introduction, cool wet weather) Southern Corn Leaf Blight: 1970 (widely planted crop, genetically uniform at one locus, selected for a virulent variant of an existing pathogen) U. S. Citrus Greening Epidemic: 2005 – present (genetically uniform crop, introduced vector, then introduced pathogen)

Jenis-jenis Patogen Tanaman Faktor-faktor yang mempengaruhi munculnya penyakit

Best way to manage plant diseases: breed for disease resistance

Emerging infectious diseases (EIDs) : used in medical science, veterinary field and apply to use in botany

Emerging infectious diseases (EIDs) are caused by pathogens that : (i) have increased in incidence, geographical or host range (ii) have changed pathogenesis (iii) have newly evolved (iv) have been discovered or newly recognized

The emergence of plant EIDs factors • Pathogen pollution : the movement of pathogen outside their natural geographical or host-species range • Climate change : temperature, precipitate • Agriculture change : intensification, diversification, globalization

Climate change • Temperature • Precipitation • Carbon dioxide concentration

Global climate change

• Industrial activity, from the burning of fossil fuels such as coal, oil, and gas, generates CO 2 and other gases which trap the sun’s ray in the atmosphere and enhance the natural “greenhouse effect” (Gore, 2006).

CO 2 /ppm 800 700 600 500 400 300 200 100 0 290 360 379 CO 2 /ppm 1800 1995 years 2006 f uture • Before the early 1800 s the atmosphere contained about 290 ppm CO 2 • 1995 the figure was 360 ppm • According to World Organization, CO 2 reached 379 ppm in 2006. • It is estimated the CO 2 level will increase to 800 ppm by the end of the century and bring serious consequences to plants (IPCC, 2001).

• Changes in the frequency of temperature may have a greater effect on biological and agricultural systems than changes in mean climate. • Projected changes of periods of higher humidity / precipitation will increase plant diseases (Carroll and Wilcox, 2003; Pardo et al. , 2005) and result in the need for extensive disease control.

Impact of climate change in agriculture

ce, vir Path ule og nce en , ab un dan of e dis nt me ing on favor vir En ions dit con Amount of disease of tal ase To To etc Effect of Environment on Plant Disease Development Total of conditions favoring susceptibility Host The disease triangle • In general, epidemics of plant disease occur as the result of interactions among three major factors • Population of plant • Population of pathogens • The environment

Impact of climate change • Pathogen (elevate temperature) - increase winter survival of plant pathogen, accelerated vector and pathogen life cycles - survive outside their historic range - geographic expansion of pathogen - Influence pathogen populations reproduce sexually or asexually

Impact of climate change • Plant (elevated CO 2) - increase leaf area, leaf thickness - higher number of leaves, total leaves area per plant - enhance photosynthesis - increase water use efficiency increase infection rates

Impact of climate change • Plant (elevated temperature) - wilting - leaf burn - leaf folding - abscission affect susceptibility to pathogen

Impact of climate change Dampak langsung perubahan iklim terhadap kesehatan tanaman: § Meningkatkan evolusi patogen § Memperpendek periode inkubasi untuk meningkatkan stres abiotik disebabkan ketidakcocokan ekosistem dan iklimnya dan lebih sering terjadinya cuaca yang ekstrim. § Kekeringan diduga menyebabkan meningkatnya patogen pada tanaman, terutama disebabkan pengaruh secara tidak langsung terdadap fisiologi inang. § Kekeringan juga dapat menyebabkan pengaruh langsung terhadap patogen.

Impact of climate change § Pemanasan global juga berhubungan dengan perubahan inang tanaman bagi beberapa jenis jamur. § Pengaruh langsung dari pemanasan global adalah meningkatnya polutan dan konsentrasi CO 2 yang akan diikuti oleh introduksi spesies patogen baru yang invasif.

Researches

Downy mildew (Plasmopara viticola) epidemic on grapevine under climate change

RESULTS • The climate change model predicted air temperature increases and rainfall reductions leading to increase in disease pressure from P. viticola • under climate change, warmer temperature can significantly increase the opportunities for the pathogen to growth, leading to increase of downy mildew pressure in grapevine in the coming decade

Lower expression of HR and other genes associated with disease resistance in big bluestem in response to simulated precipitation change Travers et al. 2007 Steve Travers

Phytohormone responses to disease and drought stress in big bluestem Erin Frank Jasmonic acid and salicylic acid increase in response to rust infection in plants without drought stress Under drought stress, plants don’t respond in this way Drought stress doubles disease severity in this system

Lesion length (cm) Xa resistance genes, except Xa 7, are less effective at higher 3. 5 temperatures a 2. 5 35°C day/29°C night 29°C day/21°C night a b 1. 5 b 0. 5 a b a a Xa 3 Xa 4 xa 5 Xa 7 Xa 10 Rice bacterial blight resistance gene c/o Jan Leach Webb et al. , unpubl.

Stomatal closure and leaf growth inhibition during drought (e. g. , Chaves et al. 2003) Plant structural changes in response to CO 2 (Pritchard et al. 1999) Higher fecundity of Colletotrichum gloeosporioides under increased CO 2 (Chakraborty and Datta 2003)

Phytophthora cinnamomi predicted expansion in Europe due to temperature change from General Circulation Models (Bergot et al. 2004)

Soybean rust pathogen immigration to US potentially via Hurricane Ivan Invasive species Kudzu will probably play important role in epidemiology Dry conditions have probably slowed movement through the US

The Impacts of Global Warming on Plant Pathogenic Bacteria Temperature • Air Temperature • Temperature can direct affect the multiplication of pathogenic bacteria, influencing the incidence of disease development. • The optimum , maximum , and minimum growth temperature are different, depending on the species or strain of bacteria

heatloving bacteria

Ralstonia spp. • R. solanacearun (RS), a soilborne pathogen with a very wide host range. • Gram-negative. It colonies the xylem, causing a bacterial wilt. • The common R. solanacearum race 3 biovar 1 strain is found in solanaceous crops throughout the tropic and subtropics (Kelman, 1953; Titatarn, 1986). • In this cause Thailand founded race 1 biovar 3, biovar 4. - biovar 3 Solanaceae - biovar 4 Zingiberraceae

Burkholderia spp. • Burkholderia includes several important pathogen : • B. glumae on rice; • B. gladioli on onion, garlic, orchid and gladiolus and has emerged as a serious, widespread disease in many Burkholderia glumae colony on King’s medium B medium different orchids in Thailand (P. Thammakijjawat, Thailand Department of Agriculture, personal communications). ; • B. andropogonis on sorghum, jojoba Bacteria is optimum growth temperature at 32 -36°C ; most grow well at 41 -42°C

Bacterial panicle blight infect ion of rice heads in the field showing cluster of upright discolored heads Gladiolus plant inoculated with B. gladioli Bacterial panicle blight infection of rice grain showing characteristic two tone discoloration symptom B. gladioli was described in Thailand on Dendrobium orchids in 1983 (Chuenchitt et al )

Acidovorax spp. Bacterial isolates recovered on nutrient agar (NA) • Gram-negative, oxidase positive, non-fluorescent on King’s medium B, • Growth at 41°C • Acidovorax avenae subsp. avenae has emerged as a disease of upland rice in Southern Europe during periods of high temperature • A. avenae subsp. citrulli cause of Bacterial fruit blotch (BFB) is a disease of watermelon and other cucurbit crops.

Water-soaked spots on the surface and cotyledon of a honeydew fruit infected with Acidovorax avenae subsp. citrulli. (Courtesy R. Walcott) corn wheat Bacterial brown stripe Causal organism: Acidovorax avenae subsp. avenae (Willems et al. 1992)

Banana Xanthomonas Wilt in East Africa A widely planted crop selected for an emerging pathogen

Bananas: World’s 4 th most important food crop Less than 10% are grown for export; 90% are locally consumed • Nutritious • Productive • Adaptable

Sub-Saharan Africa grows 1/3 of the world’s bananas

Bananas supply 30 -60% of daily calories in Uganda, Rwanda & Burundi

Bananas are also a major source of cash income

Each Ugandan eats ~ 0. 45 kg of bananas a year

In 2001 a new banana disease appeared in Africa: Banana Xanthomonas Wilt, or BXW

Symptoms of BXW: • Yellowed, dying leaves • Early fruit ripening • Wilted male flowers • Discolored, inedible fruits

The Guilty Party: Xanthomonas campestris pv. museacearum, a rapidly emerging new pathogenic bacterium

Bacteria ooze from flowers & cut stems, are easily transmitted by pollinators & machetes

Impact of BXW in the African Great Lakes Region: Production loss estimated at 53% ~$8 billion over past 10 years Cooking banana prices up by 40% in Uganda Increased hunger

• Food insecurity • Internal migration • Kids leave school A dying banana plantation is a family catastrophe:

Conclusions • Plant disease has a major impact on agricultural and natural systems • Current strategies for management need to be maintained and improved, even if the climate did not change • Climate change will increase some disease risks and decrease others • The effects of climate change will be most important when thresholds and interactions occur to produce unanticipated large responses • Systems may change more rapidly than in the past, requiring more research and policy attention

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