Editing Wheat (section)

=== For disease resistance ===

[[File:Stem rust on differential lines wheat.jpg|thumb|Different strains have been infected with the [[stem rust|stem rust fungus]]. The strains bred to be resistant have their leaves unaffected or relatively unaffected by the fungus.]]

Wild grasses in the genus ''Triticum'' and related genera, and grasses such as [[rye]] have been a source of many disease-resistance traits for cultivated wheat [[Transgenic plant|breeding]] since the 1930s.<ref>{{cite journal |last1=Hoisington |first1=D. |last2=Khairallah |first2=M. |last3=Reeves |first3=T. |last4=Ribaut |first4=J.M. |last5=Skovmand |first5=B. |last6=Taba |first6=S. |last7=Warburton |first7=M. |display-authors=3 |year=1999 |title=Plant genetic resources: What can they contribute toward increased crop productivity? |journal=[[Proceedings of the National Academy of Sciences]]|volume=96 |issue=11 |pages=5937–43 |pmid=10339521 |doi=10.1073/pnas.96.11.5937  |pmc=34209|bibcode=1999PNAS...96.5937H |doi-access=free }}</ref> Some [[plant disease resistance|resistance gene]]s have been identified against ''[[Pyrenophora tritici-repentis]]'', especially races 1 and 5, those most problematic in [[Kazakhstan]].<ref name="Dahm-2021">{{cite web |first1=Madeline |last1=Dahm |title=Genome-wide association study puts tan spot-resistant genes in the spotlight |website=[[WHEAT (CGIAR)|WHEAT]] |date=27 July 2021 |url=http://wheat.org/genome-wide-association-study-puts-tan-spot-resistant-genes-in-the-spotlight/ |access-date=28 July 2021 |archive-date=22 September 2021 |archive-url=https://web.archive.org/web/20210922142934/https://wheat.org/genome-wide-association-study-puts-tan-spot-resistant-genes-in-the-spotlight/ |url-status=dead }}</ref> [[crop wild relative|Wild relative]], ''[[Aegilops tauschii]]'' is the source of several genes effective against [[TTKSK]]/Ug99 - ''[[Sr33 (gene)|Sr33]]'', ''Sr45'', ''Sr46'', and ''SrTA1662'' - of which ''Sr33'' and ''SrTA1662'' are the work of Olson ''et al.'', 2013, and ''Sr45'' and ''Sr46'' are also briefly reviewed therein.<ref name="Bohra-2021">{{cite journal |last1=Bohra |first1=Abhishek |last2=Kilian |first2=Benjamin |last3=Sivasankar |first3=Shoba |last4=Caccamo |first4=Mario |last5=Mba |first5=Chikelu |last6=McCouch |first6=Susan R. |last7=Varshney |first7=Rajeev K. |title=Reap the crop wild relatives for breeding future crops |journal=[[Trends in Biotechnology]] |publisher=[[Cell Press]] |year=2021 |volume=40 |issue=4 |doi=10.1016/j.tibtech.2021.08.009 |pages=412–431|pmid=34629170 |s2cid=238580339 |doi-access=free }}</ref>

*''{{visible anchor|Lr67}}'' is an [[R gene]], a [[dominant negative]] for [[partial adult plant resistance|partial adult resistance]] discovered and molecularly characterized by Moore ''et al.'', 2015. {{As of|2018}} ''Lr67'' is effective against all races of [[wheat leaf rust|leaf]], [[wheat stripe rust|stripe]], and [[wheat stem rust|stem]] rusts, and [[wheat powdery mildew|powdery mildew]] (''Blumeria graminis''). This is produced by a [[mutation]] of two [[amino acid]]s in what is [[gene prediction|predicted to be]] a [[hexose transporter]]. The product then [[heterodimerization|heterodimerizes]] with the [[plant susceptibility allele|susceptible's]] product, with the downstream result of reducing [[glucose]] uptake.<ref name="Kourelis-2018">{{cite journal |last1=Kourelis |first1=Jiorgos |last2=van der Hoorn |first2=Renier A.L. |title=Defended to the Nines: 25 Years of Resistance Gene Cloning Identifies Nine Mechanisms for R Protein Function |journal=[[The Plant Cell]] |publisher=[[American Society of Plant Biologists]] ([[Oxford University Press|OUP]]) |volume=30 |issue=2 |date=2018-01-30 |doi=10.1105/tpc.17.00579 |pages=285–299|pmid=29382771 |pmc=5868693 |bibcode=2018PlanC..30..285K }}</ref>
*''{{visible anchor|Lr34}}'' is widely deployed in cultivars due to its abnormally broad effectiveness, conferring resistance against [[wheat leaf rust|leaf-]] and [[wheat stripe rust|stripe-]]rusts, and [[wheat powdery mildew|powdery mildew]].<ref name="Dodds-2010">{{cite journal |last1=Dodds |first1=Peter N. |last2=Rathjen |first2=John P. |title=Plant immunity: towards an integrated view of plant–pathogen interactions |journal=[[Nature Reviews Genetics]] |publisher=[[Nature Portfolio]] |volume=11 |issue=8 |date=2010-06-29 |doi=10.1038/nrg2812 |pages=539–548|pmid=20585331 |hdl=1885/29324 |s2cid=8989912 |hdl-access=free }}</ref> An important quantitative resistance gene, Lr34, has been isolated and used intensively in wheat cultivation worldwide; it provides a novel resistance mechanism.<ref name="Krattinger-2009">{{cite journal |last1=Krattinger |first1=Simon G. |last2=Lagudah |first2=Evans S. |last3=Spielmeyer |first3=Wolfgang |last4=Singh |first4=Ravi P. |last5=Huerta-Espino |first5=Julio |last6=McFadden |first6=Helen |last7=Bossolini |first7=Eligio |last8=Selter |first8=Liselotte L. |last9=Keller |first9=Beat |display-authors=6 |title=A Putative ABC Transporter Confers Durable Resistance to Multiple Fungal Pathogens in Wheat |journal=Science |volume=323 |issue=5919 |date=2009-03-06 |issn=0036-8075 |doi=10.1126/science.1166453 |pages=1360–1363|pmid=19229000 |bibcode=2009Sci...323.1360K }}</ref><ref name="Krattinger-2019">{{cite journal |last1=Krattinger |first1=Simon G. |last2=Kang |first2=Joohyun |last3=Bräunlich |first3=Stephanie |last4=Boni |first4=Rainer |last5=Chauhan |first5=Harsh |last6=Selter |first6=Liselotte L. |last7=Robinson |first7=Mark D. |last8=Schmid |first8=Marc W. |last9=Wiederhold |first9=Elena |last10=Hensel |first10=Goetz |last11=Kumlehn |first11=Jochen |last12=Sucher |first12=Justine |last13=Martinoia |first13=Enrico |last14=Keller |first14=Beat |display-authors=6 |title=Abscisic acid is a substrate of the ABC transporter encoded by the durable wheat disease resistance gene Lr34 |journal=New Phytologist |volume=223 |issue=2 |date=2019 |issn=0028-646X |pmid=30913300 |pmc=6618152 |doi=10.1111/nph.15815 |pages=853–866|bibcode=2019NewPh.223..853K }}</ref> Krattinger et al. 2009 find ''Lr34'' to be an [[ATP-binding cassette transporter|ABC transporter]], and conclude that this is the probable reason for its effectiveness<ref name="Dodds-2010" /><ref name="Furbank-2011">{{cite journal |last1=Furbank |first1=Robert T. |last2=Tester |first2=Mark |title=Phenomics – technologies to relieve the phenotyping bottleneck |journal=[[Trends in Plant Science]] |publisher=[[Cell Press]] |volume=16 |issue=12 |year=2011 |doi=10.1016/j.tplants.2011.09.005 |pages=635–644|pmid=22074787 |bibcode=2011TPS....16..635F }}</ref> and the reason that it produces a 'slow rusting'/[[adult plant resistance|adult resistance]] phenotype.<ref name="Furbank-2011" />
* ''{{ Visible anchor |Pm8 }}'' is a widely used [[wheat powdery mildew|powdery mildew]] resistance [[introgressed]] from [[rye]] (''[[Secale cereale]]'').<ref name="Herrera-2017" /> It comes from the rye [[1R (chromosome)|1R chromosome]], a source of many resistances since the 1960s.<ref name="Herrera-2017">{{cite journal |pages=1–9 |year=2017 |issue=1 |volume=154 |publisher=[[BioMed Central]] |journal=[[Hereditas]] |first3=Inger |first2=Larisa |first1=Leonardo |last3=Åhman |last2=Gustavsson |last1=Herrera |doi=10.1186/s41065-017-0033-5 |title=A systematic review of rye (''Secale cereale'' L.) as a source of resistance to pathogens and pests in wheat (''Triticum aestivum'' L.)|pmid=28559761 |pmc=5445327 |doi-access=free }}</ref>

{{visible anchor|Fusarium head blight resistance|text=[[Fusarium head blight resistance|Resistance to Fusarium head blight]]}} (FHB, Fusarium ear blight) is also an important breeding target. [[Marker-assisted breeding]] panels involving [[kompetitive allele specific PCR]] can be used. Singh et al. 2019 identify a KASP [[genetic marker]] for a [[pore-forming toxin]]-like gene providing FHB resistance.<ref name="Kaur-2020">{{cite journal |last1=Kaur |first1=Bhavjot |last2=Mavi |first2=G. S. |last3=Gill |first3=Manpartik S. |last4=Saini |first4=Dinesh Kumar |title=Utilization of KASP technology for wheat improvement |journal=Cereal Research Communications |publisher=Springer Science+Business Media |volume=48 |issue=4 |date=2020-07-02 |doi=10.1007/s42976-020-00057-6 |pages=409–421 |s2cid=225570977}}</ref>

In 2003 the first resistance genes against fungal diseases in wheat were isolated.<ref name="Feuillet-2003">{{cite journal |last1=Feuillet |first1=Catherine |last2=Travella |first2=Silvia |last3=Stein |first3=Nils |last4=Albar |first4=Laurence |last5=Nublat |first5=Aurélie |last6=Keller |first6=Beat |title=Map-based isolation of the leaf rust disease resistance gene Lr10 from the hexaploid wheat ( Triticum aestivum L.) genome |journal=Proceedings of the National Academy of Sciences |volume=100 |issue=25 |date=2003-12-09 |issn=0027-8424 |pmid=14645721 |pmc=299976 |doi=10.1073/pnas.2435133100 |pages=15253–15258|doi-access=free |bibcode=2003PNAS..10015253F }}</ref><ref name="Yahiaoui-2004">{{cite journal |last1=Yahiaoui |first1=Nabila |last2=Srichumpa |first2=Payorm |last3=Dudler |first3=Robert |last4=Keller |first4=Beat |title=Genome analysis at different ploidy levels allows cloning of the powdery mildew resistance gene Pm3b from hexaploid wheat |journal=The Plant Journal |volume=37 |issue=4 |date=2004 |issn=0960-7412 |doi=10.1046/j.1365-313X.2003.01977.x |pages=528–538|pmid=14756761 }}</ref> In 2021, novel resistance genes were identified in wheat against [[powdery mildew]] and [[wheat leaf rust]].<ref name="Sánchez-Martín-2021">{{cite journal |last1=Sánchez-Martín |first1=Javier |last2=Widrig |first2=Victoria |last3=Herren |first3=Gerhard |last4=Wicker |first4=Thomas |last5=Zbinden |first5=Helen |last6=Gronnier |first6=Julien |last7=Spörri |first7=Laurin |last8=Praz |first8=Coraline R. |last9=Heuberger |first9=Matthias |last10=Kolodziej |first10=Markus C. |last11=Isaksson |first11=Jonatan |last12=Steuernagel |first12=Burkhard |last13=Karafiátová |first13=Miroslava |last14=Doležel |first14=Jaroslav |last15=Zipfel |first15=Cyril |last16=Keller |first16=Beat |display-authors=6 |title=Wheat Pm4 resistance to powdery mildew is controlled by alternative splice variants encoding chimeric proteins |journal=Nature Plants |volume=7 |issue=3 |date=2021-03-11 |issn=2055-0278 |pmid=33707738 |pmc=7610370 |doi=10.1038/s41477-021-00869-2 |pages=327–341|bibcode=2021NatPl...7..327S }}</ref><ref name="Kolodziej-2021">{{cite journal |last1=Kolodziej |first1=Markus C. |last2=Singla |first2=Jyoti |last3=Sánchez-Martín |first3=Javier |last4=Zbinden |first4=Helen |last5=Šimková |first5=Hana |last6=Karafiátová |first6=Miroslava |last7=Doležel |first7=Jaroslav |last8=Gronnier |first8=Julien |last9=Poretti |first9=Manuel |last10=Glauser |first10=Gaétan |last11=Zhu |first11=Wangsheng |last12=Köster |first12=Philipp |last13=Zipfel |first13=Cyril |last14=Wicker |first14=Thomas |last15=Krattinger |first15=Simon G. |last16=Keller |first16=Beat |display-authors=6 |title=A membrane-bound ankyrin repeat protein confers race-specific leaf rust disease resistance in wheat |journal=Nature Communications |volume=12 |issue=1 |date=2021-02-11 |page=956 |issn=2041-1723 |pmid=33574268 |pmc=7878491 |doi=10.1038/s41467-020-20777-x|bibcode=2021NatCo..12..956K }}</ref>
Modified resistance genes have been tested in transgenic wheat and barley plants.<ref name="Koller-2023">{{Cite journal |last1=Koller |first1=Teresa |last2=Camenzind |first2=Marcela |last3=Jung |first3=Esther |last4=Brunner |first4=Susanne |last5=Herren |first5=Gerhard |last6=Armbruster |first6=Cygni |last7=Keller |first7=Beat |display-authors=6 |date=2023-12-10 |title=Pyramiding of transgenic immune receptors from primary and tertiary wheat gene pools improves powdery mildew resistance in the field |journal=Journal of Experimental Botany |volume=75 |issue=7 |pages=1872–1886 |doi=10.1093/jxb/erad493 |issn=0022-0957 |doi-access=free|pmid=38071644 |pmc=10967238 }}</ref>
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