I-Fusarium xylarioides, i-fungus ephuma emhlabeni ibangela "isifo se-Coffee wilt" esinembali yokubangela umonakalo omkhulu kwizityalo zekofu. Kwabakho ukuqhambuka kwesi sifo ngo-1920 esasilawulwa ngokufanelekileyo. Nangona kunjalo, esi sifo siphinde sadibana ngexesha elifanelekileyo sakhokelela ekuqhambukeni okubangele umonakalo omkhulu wezityalo. Uphononongo lwangaphambili lubonise ukuba i-causative fungal specie inokuba yavela ngokufumana imizila yemfuza evela kuhlobo olunxulumeneyo. Uphononongo olupapashwe nge-5 kaDisemba 2024 luye lwaqinisekisa ukuba ukuvela kwakhona kwesifo se-kofu wilt ngenxa yokudluliselwa kwemfuza okuthe tye ukusuka kwiintlobo zefungal ezinxulumene ne-Fusarium oxysporum ukuya kwi-causative specie i-Fusarium xylarioides eyavumela iintlobo ze-fungal ze-causal ukuba ziguquke kwaye zifumane ezifanelekileyo. iimpawu zokosulela izityalo ezikhokelela ekuveleni kwakhona koqhambuko kunye nomonakalo kwizityalo zekofu.
Kubunjineli bemfuza, ijini entsha yemfuza okanye iDNA ikhutshelwa ngobuqhetseba kwiseli yento ephilayo kusetyenziswa iivektha ezifana neeplasmids okanye iivayirasi ezilungisiweyo ukwazisa isakhono esitsha kwizinto eziphilayo.
Ngokwendalo, ukudluliselwa kofuzo okanye ukudluliselwa kolwazi lwemfuza kwenzeka ngokuzala ngokuthe nkqo ukusuka kubazali ukuya kwinzala ukuya kwizizukulwana. Olu luphawu oluxhaphakileyo kwi-eukaryotes olubenza bakwazi ukufumana ukwahluka ukuze baziqhelanise nendaleko. Kwiiprokaryotes ezifana neebhaktheriya, nangona kunjalo, izinto zofuzo zihanjiswa ngokuthe tye (okanye ecaleni) phakathi kwezinto eziphilayo zesizukulwana esifanayo ngaphandle kokubandakanya ukuveliswa. Oku kubizwa ngokuba yi-horizontal gene transfer (HGT) kwaye kuphela kwendlela ibhaktheriya enokufumana ngayo uhlobo olutsha lokuziqhelanisa noxinzelelo lokukhetha okungalunganga kwaye iguquke ukuze iphile. Oku kunokwenzeka ngokugqithiselwa kwe-DNA kwindalo esingqongileyo kunye nokudityaniswa kwayo kwikhromozomu yebhaktiriya okanye iplasmid (utshintsho). Imfuza inokudluliselwa ngokuthe tye ukusuka kwibhaktiriya enye ukuya kwenye ngentsholongwane eyosulela ibhaktheriya okanye i-bacteriophages (ukudluliselwa), okanye ngokugqithiselwa ngokuthe ngqo kohlobo lwemfuza ukusuka kwiseli yebhaktiriya yomxhasi ukuya kwiseli yomamkeli nge-sex pilus (conjugation).
Nangona ibonwa kakhulu kwiprokaryotes, ukuhanjiswa kwemfuza okuthe tye kunxulunyaniswa ne-eukaryotes ngokunjalo. I-Endosymbiosis iyaziwa ukuba idlale indima kwi-eukaryotic evolution ngokusebenzisa ibhaktheriya-eukaryote gene transfer. Iziganeko ezininzi zokudluliselwa kofuzo lwe-eukaryote -eukaryote zibhaliwe.
Isenzeko sodluliselo lwemfuza oluthe tyaba lubalulekile kuba lunegalelo kwindaleko. Umzekelo, Oku kunoxanduva lophuhliso lwentsholongwane enganyangekiyo ngamachiza/amachiza amaninzi ebhaktheriya engumba omkhulu wempilo yoluntu. Kwezolimo, indima ethe tyaba yokudluliselwa kwemfuza phakathi kweentlobo zokungunda ezinxulumeneyo kudala kukrokreleka ekuqhambukeni kwesifo sokubola kwekofu.
Isifo seKofu
Ikofu sisityalo esibalulekileyo sorhwebo. Ubungakanani bayo bemarike yehlabathi buqikelelwa ukuba bumalunga ne-223 yeebhiliyoni zeedola. Isityalo sekofu siyinxalenye yeCoffea. Ineentlobo ezininzi, kodwa iintlobo zeArabica kunye neRobusta zezona zidumileyo kubalwa kuninzi lwemveliso yehlabathi. Coffea arabica Ibalelwa kwi-60-80% yemveliso yekofu yehlabathi, ngelixa Coffea canephora (eyaziwa ngokuba yiCoffea robusta) Ibalelwa malunga nama-20–40%.
Isifo sekofu sibangelwa ngumngundo ofumaneka emhlabeni I-Fusarium xylarioides efumana ukungena ngeengcambu zesityalo ukwenza ikholoni ye-xylem ithobisa iindonga zeeseli zezondlo. Ithintela ukungena kwamanzi okukhokelela ekubuneni kwezityalo. Umngundo ezinxulumene IFusarium oxysporum Ikwayipathogen esasazwa ngumhlaba esasazeka emhlabeni kwaye inoxanduva lokutshabalalisa izifo kwizityalo ezininzi ezifana nesifo sePanama kwiibhanana, i-tomato vascular wilt njl. F. oxysporum uhlala kwezinye izityalo (ezifana nebhanana) zilinywa kunye nekofu ukuze zibe nomthunzi kodwa wabelana nekofu njengomninimzi F. xylarioides.
Ukusukela ngeminyaka yee-1920s, izityalo zekofu e-Afrika ziye zafumana ukuqhambuka kwesifo sowilt esinefuthe elibi kwikofu. Mveliso kunye nokuphila kwamafama, ngakumbi e-Ethiopia nakumbindi we-Afrika. Uqhambuko lokuqala ngeminyaka yoo-1920s lwalawulwa ngempumelelo kusetyenziswa iindlela ezifanelekileyo kodwa isifo saphinda savela ngo-2000s. Ngaba umngundo causative I-Fusarium xylarioides yenze indaleko emva koqhambuko lokuqala ngo-1920s ukuze kwandiswe amandla okosulela izityalo zekofu ezikhokelela kuqhambuko kwakhona? Kwakukho imiqondiso evela kwizifundo ukuba F. xylarioides imfuza efunyenweyo yokwandisa amandla okosulela.
Uphononongo lwembali ye-genomics olwapapashwa ngo-2021 lwaxhasa uluvo lokuba i-arabica kunye nezityalo zekofu ye-robusta ngokuyinxenye zifumene uhlobo oluthile lwefuthe lofuzo ngokugqithiselwa ngokuthe tye ukusuka. F. oxysporum. Iijini ze-Effector zidibanisa iimolekyuli ezibandakanyekayo ekumiseni izifo. Ezi zofuzo zibonakaliswa kuwo wonke umjikelo wobomi bomngundo ukuxhasa inkqubo yesifo.
Kuphononongo lwakutsha nje olupapashwe nge-5 kaDisemba 2024, abaphandi baqhube ucazululo lothelekiso lwe-genomic kwiintlobo ezili-13 zembali F. oxysporum ukuqonda ukuba izifo ezibangela umngundo zavela njani kwaye ziqhelaniswe nezityalo zayo zekofu. Kwafunyaniswa ukuba F. Xylarioides inemizila emine eyahlukileyo: enye ilungelelaniswe nezityalo zekofu ye-arabica, enye ilungelelaniswe nezityalo zekofu ye-robusta, kunye nemigca emibini yembali eyayihlala kwiintlobo zekofu ezinxulumene. Ngaphaya koko, ezi ntlobo zeentlobo zifumene iijini ezibalulekileyo kwezinxulumeneyo F. oxysporum, nto leyo eyenza ukuba kube ngunobangela wesifo F. xylarioides ukudiliza iindonga zeeseli zezityalo zekofu ukuze kubangele isifo se-wilt. I eukaryote-eukaryote oxwesileyo gene transfer ukusuka F. oxysporum ukuba F. xylarioides yavumela yangaphambili ukuba yosulele izityalo zekofu ngokufanelekileyo ukwenza ukuvela kwakhona kwesifo seCoffee wilt kwenzeke.
Oku kuqonda indlela esibangelwa ngayo esi sifo kunokuba luncedo ekulungiseni kakuhle iindlela zolimo kunye nokulawula izifo zezityalo ngokufanelekileyo.
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Iingxelo:
- IYunivesithi yaseColorado Denver. UTshintsho lwemfuza oluthe tyaba – isikhokelo somsebenzi. Ifumaneka e https://www.ucdenver.edu/docs/librariesprovider132/a-sync_sl/genetics/upload-2/bacterial-genetics/horizontal-gene-transfer-activity-guide.pdf
- Keeling, P., Palmer, J. Ukudluliselwa kwemfuza okuthe tye kwi-eukaryotic evolution. UNat Rev Genet 9, 605–618 (2008). https://doi.org/10.1038/nrg2386
- Peck, LD, et al. Imbali ye-genomics ityhila iindlela zokuzivelela emva koqhambuko lwekofu ekhethekileyo yefusarium xylarioides. I-BMC Genomics 22, 404 (2021). Ipapashwe: 04 Juni 2021. DOI: https://doi.org/10.1186/s12864-021-07700-4
- Peck LD, et al. Ukudluliselwa okuthe tyaba phakathi kweentlobo ze-Fusarium zokungunda kube negalelo ekuqhambukeni okulandelelanayo kwesifo sokubola kwekofu. Ibhayoloji yePLoS. Ipapashwe: 5 December 2024. DOI: https://doi.org/10.1371/journal.pbio.3002480
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