Izitshalo zinde kakhulu, ziyagoba ukuze kufinyelele ukukhanya kwelanga eqabungeni ngalinye. Naphezu kokubona lesi simo amakhulu eminyaka, ososayensi abasiqondi ngokugcwele. Manje ososayensi e-Salk Institute bathole ukuthi izici ezimbili zezitshalo - i-protein PIF7 kanye ne-hormone yokukhula i-auxin - ziyizisusa ezisheshisa ukukhula lapho izitshalo zisethunzini futhi zivezwe emazingeni okushisa aphezulu ngesikhathi esisodwa. iwebhusayithi esemthethweni yesikhungo.
Okutholakele, okushicilelwe kumagazini i-Nature Communications ngo-Agasti 29, 2022, kuzosiza ososayensi babikezele ukuthi izitshalo zizosabela kanjani ekushintsheni kwesimo sezulu futhi zandise isivuno naphezu kokushisa komhlaba okulimaza izitshalo.
"Okwamanje, sitshala izitshalo ngenani elithile, kodwa imiphumela yethu ikhombisa ukuthi kuzodingeka sehlise lokho kuminyana ukuze sikhulise ukukhula kwezitshalo njengoba isimo sezulu sishintsha," kusho umlobi ophezulu uSolwazi Joanne Chory, umqondisi weSalk Institute's Plant Molecular. kanye ne-Cell Biology Laboratory kanye no-Howard, umcwaningi e-Hughes Medical Institute. "Ukuqonda isisekelo samangqamuzana sendlela izitshalo ezisabela ngayo ekukhanyeni namazinga okushisa kuzosivumela ukuba silungise kahle ukuminyana kokutshala ukuze sikhiqize isivuno esihle kakhulu."
Ngesikhathi sokuhluma, izithombo zelula ngokushesha iziqu zazo ukuze zibhodloze inhlabathi futhi zibambe ukukhanya kwelanga ngokushesha ngangokunokwenzeka. Ngokuvamile, isiqu sinciphisa ukukhula kwaso ngemva kokuchayeka elangeni. Kodwa isiqu singanwebeka ngokushesha futhi uma isitshalo siqhudelana nezitshalo ezizungezile ngokuthola ukukhanya kwelanga noma sandisa ibanga phakathi kwendawo eshisayo namaqabunga esitshalo ngenxa yokukhuphuka kwamazinga okushisa. Nakuba kokubili izimo zemvelo - shading namazinga okushisa aphezulu - zikhuthaza ukukhula kwesiqu, nazo zinciphisa isivuno.
Kulolu cwaningo, ososayensi baqhathanisa izitshalo ezikhula emthunzini namazinga okushisa afudumele ngesikhathi esifanayo - izimo ezilingisa ukuminyana okuphezulu kokutshala nokushintsha kwesimo sezulu. Ososayensi basebenzise isitshalo esiyimodeli i-Arabidopsis thaliana, kanye notamatisi nesihlobo esiseduze sikagwayi, ngoba babenesithakazelo sokubona ukuthi zonke izinhlobo zezitshalo ezintathu zithinteka ngokulinganayo yini kulezi zimo zemvelo.
Kuzo zontathu lezi zinhlobo, ithimba labacwaningi lathola ukuthi izitshalo zakhula zibe zinde kakhulu lapho ngesikhathi esifanayo zizama ukugwema umthunzi owenziwe izitshalo ezingomakhelwane futhi zichayeka emazingeni okushisa aphakeme. Ezingeni lamangqamuzana, abacwaningi bathola ukuthi i-PIF7 transcription factor, iphrotheni esiza ukuvula nokuvala izakhi zofuzo, yasiza ukukhulisa ukukhula. Baphinde bathola ukuthi amazinga e-auxin, i-hormone yokukhula, anda lapho izitshalo zithola izitshalo ezingomakhelwane, ezikhuthaza ukukhula ekuphenduleni amazinga okushisa aphakeme kanyekanye. Le ndlela ye-synergistic ye-PIF7-auxin ivumele izitshalo ukuthi ziphendule endaweni yazo futhi zizijwayeze ekufuneni izimo ezingcono kakhulu zokukhula.
Isici esihlobene sokuloba, i-PIF4, siphinde savuselela ukunwetshwa kwesiqu emazingeni okushisa aphezulu. Nokho, ngokuhlanganiswa komthunzi namazinga okushisa aphakeme, lesi sici asibange sisadlala indima ebalulekile.
"Samangala ukuthola ukuthi i-PIF4 ayidlali indima ebalulekile ngoba izifundo zangaphambilini zikhombisile ukubaluleka kwalesi sici ezimweni zokukhula ezihlobene," kusho umlobi wokuqala wocwaningo u-Yogev Burko, umcwaningi e-Salk Institute kanye noprofesa ohlangene naye. Inhlangano Yocwaningo Lwezolimo e-Israel Volcanoes Institute. “Iqiniso lokuthi i-PIF7 iyona ehamba phambili ekukhuleni kwalesi sitshalo kwaba yisimangaliso sangempela. Ngalolu lwazi olusha, sinethemba lokuthi sizolungisa kahle indlela izitshalo ezikhula ngayo ukuze zizisize zivumelane nokushintsha kwesimo sezulu.”
Abacwaningi bakholelwa ukuthi kunenye into esazotholwa ekhulisa umphumela we-PIF7 ne-auxin. Bathemba ukuhlola lesi sici esingaziwa ezifundweni ezizayo. Ilebhu kaBerko izophinda ifunde ukuthi le ndlela ingenziwa kanjani kahle ezitshalweni.
“Amazinga okushisa embulunga yonke ayakhuphuka, ngakho sidinga izitshalo zokudla ezingakhula ngaphansi kwalezi zimo ezintsha,” kusho uChori, umholi ohlangene weSalk Plant Use Initiative noHoward H. kanye noMaryam R. Newman onguSihlalo wePlant Biology. “Sihlonze izinto ezibalulekile ezilawula ukukhula kwezitshalo emazingeni aphezulu okushisa, okuzosisiza ukuthi sikhule izitshalo ezikhiqizayo ukuze sondle izizukulwane ezizayo.”