Editing Rice (section)

== Biotechnology ==

=== High-yielding varieties ===

{{main|Green revolution}}

The high-yielding varieties are a group of crops created during the [[Green Revolution]] to increase global food production radically. The first Green Revolution rice variety, [[IR8]], was produced in 1966 at the [[International Rice Research Institute]] through a cross between an Indonesian variety named "Peta" and a Chinese variety named "Dee Geo Woo Gen".<ref name="Hettel 2016">{{cite web |last=Hettel |first=Gene |title=IR8—a rice variety for the ages |url=https://ricetoday.irri.org/ir8-a-rice-variety-for-the-ages/ |website=Rice Today |access-date=December 29, 2023 |date=November 18, 2016 |archive-date=December 29, 2023 |archive-url=https://web.archive.org/web/20231229205451/https://ricetoday.irri.org/ir8-a-rice-variety-for-the-ages/ |url-status=live }}</ref> Green Revolution varieties were bred to have short strong stems so that the rice would not lodge or fall over. This enabled them to stay upright and productive even with heavy applications of fertiliser.<ref name="Hettel 2016"/>

=== Expression of human proteins ===

[[Ventria Bioscience]] has [[genetically modified]] rice to [[gene expression|express]] [[lactoferrin]] and [[lysozyme]] which are [[proteins]] usually found in [[breast milk]], and [[human serum albumin]]. These proteins have [[Antiviral protein|antiviral]], [[antibacterial]], and [[Antifungal protein|antifungal]] effects.<ref>{{cite journal |last=Marris |first=E. |title=Rice with human proteins to take root in Kansas |journal=[[Nature (journal)|Nature]] |date=May 18, 2007 |s2cid=84688423 |doi=10.1038/news070514-17}}</ref> Rice containing these added proteins can be used as a component in [[oral rehydration solution]]s to treat [[diarrhea]]l diseases, thereby shortening their duration and reducing recurrence. Such supplements may also help reverse [[anemia]].<ref>{{cite journal |last1=Bethell |first1=D.R. |last2=Huang |first2=J. |title=Recombinant human lactoferrin treatment for global health issues: iron deficiency and acute diarrhea |journal=[[BioMetals (journal)|BioMetals]] |volume=17 |issue=3 |pages=337–342 |date=June 2004 |pmid=15222487 |doi=10.1023/B:BIOM.0000027714.56331.b8 |s2cid=3106602 }}</ref>

=== Flood-tolerance ===

{{Main|Deepwater rice}}

[[File:Researchers checking deep water rice.jpg|thumb|upright=1.2|International Rice Research Institute researchers checking [[deepwater rice]] in the Philippines ]]

In areas subject to [[flooding]], farmers have long planted flood tolerant varieties known as [[deepwater rice]]. In South and [[South East Asia]], flooding affects some {{convert|20|e6ha|e6acre|abbr=off}} each year.<ref name="Debrata-2012">{{cite journal |last1=Debrata |first1=Panda |last2=Sarkar |first2=Ramani Kumar |year=2012 |title=Role of Non-Structural Carbohydrate and its Catabolism Associated with Sub 1 QTL in Rice Subjected to Complete Submergence |journal=Experimental Agriculture |volume=48 |issue=4|pages=502–512 |doi=10.1017/S0014479712000397 |s2cid=86192842 }}</ref> 
Flooding has historically led to massive losses in yields, such as in the Philippines, where in 2006, rice crops worth $65&nbsp;million were lost to flooding.<ref name="IRRI-2012">"{{cite web |url=http://irri.org/index.php?option=com_k2&view=item&id=9148&lang=en |title=Climate change-ready rice |archive-url=https://web.archive.org/web/20121028234824/http://irri.org/index.php?option=com_k2&view=item&id=9148&lang=en |archive-date=October 28, 2012 |publisher=[[International Rice Research Institute]] |access-date=October 31, 2013 }}</ref>

Standard rice varieties cannot withstand stagnant flooding for more than about a week, since it disallows the plant access to necessary requirements such as sunlight and gas exchange. The Swarna Sub1 cultivar can tolerate week-long submergence, consuming carbohydrates efficiently and continuing to grow.<ref name="Debrata-2012"/> So-called "[[Scuba diving|scuba]] rice"<ref>{{cite web |last1=Gautam |first1=Priyanka |display-authors=etal |title=Nutrient Management for Enhancing Submergence Tolerance in Rice |url=https://krishi.icar.gov.in/jspui/bitstream/123456789/8940/1/Research%20Bulletin-13.pdf |publisher=National Rice Research Institute |location=Cuttack, Odisha, India |page=3 |date=2017 |quote=NRRI Research Bulletin No. 13 |access-date=May 13, 2024 |archive-date=June 3, 2024 |archive-url=https://web.archive.org/web/20240603200729/https://krishi.icar.gov.in/jspui/bitstream/123456789/8940/1/Research%20Bulletin-13.pdf |url-status=live }}</ref> with the Sub1A [[transgene]] is robustly tolerant of submergence for as long as two weeks, offering much improved flood survival for farmers' crops. IRRI has created Sub1A varieties and distributed them to Bangladesh, India, Indonesia, Nepal, and the Philippines.<ref name="Emerick Ronald 2019">{{cite journal |last1=Emerick |first1=Kyle |last2=Ronald |first2=Pamela C. |title=Sub1 Rice: Engineering Rice for Climate Change |journal=[[Cold Spring Harbor Perspectives in Biology]] |volume=11 |issue=12 |date=2019 |pmid=31182543 |pmc=6886445 |doi=10.1101/cshperspect.a034637 |page=a034637}}</ref>

===Drought-tolerance===

[[Drought]] represents a significant environmental stress for rice production, with {{convert|19-23|e6ha|e6acre|abbr=off}} of rainfed rice production in South and South East Asia often at risk.<ref name="irri.org">{{cite web |url=http://irri.org/index.php?option=com_k2&view=item&id=9952:drought-submergence-an |title=Drought, submergence and salinity management |archive-url=https://web.archive.org/web/20131101131821/http://irri.org/index.php?option=com_k2&view=item&id=9952%3Adrought-submergence-an |archive-date=November 1, 2013 |work=International Rice Research Institute (IRRI) |access-date=September 29, 2013 }}</ref><ref name="IRRI-2014">"{{cite web |url=http://irri.org/our-work/research/better-rice-varieties/climate-change-ready-rice |title=Climate change-ready rice |archive-url=https://web.archive.org/web/20140314033307/http://irri.org/our-work/research/better-rice-varieties/climate-change-ready-rice |archive-date=March 14, 2014 |publisher=[[International Rice Research Institute]] (IRRI) |access-date=September 29, 2013 }}</ref> Under drought conditions, without sufficient water to afford them the ability to obtain the required levels of [[nutrients]] from the soil, conventional commercial rice varieties can be severely affected—as happened for example in India early in the 21st century.<ref name="Palmer-2013">{{cite web |url=http://www.ciatnews.cgiar.org/2013/08/06/newly-discovered-rice-gene-goes-to-the-root-of-drought-resistance/ |title=Newly-discovered rice gene goes to the root of drought resistance |archive-url=https://web.archive.org/web/20131103182251/http://www.ciatnews.cgiar.org/2013/08/06/newly-discovered-rice-gene-goes-to-the-root-of-drought-resistance/ |archive-date=November 3, 2013 |last=Palmer |first=Neil |date=2013 |publisher=[[International Center for Tropical Agriculture]] |access-date=September 29, 2013 }}</ref>

The [[International Rice Research Institute]] conducts research into developing drought-tolerant rice varieties, including the varieties Sahbhagi Dhan, Sahod Ulan, and Sookha dhan, currently being employed by farmers in India, the Philippines, and Nepal respectively.<ref name="IRRI-2014" /> In addition, in 2013 the Japanese National Institute for Agrobiological Sciences led a team which successfully inserted the ''DEEPER ROOTING 1'' (''DRO1'') gene, from the Philippine [[Upland and lowland (freshwater ecology)|upland]] rice variety Kinandang Patong, into the popular commercial rice variety IR64, giving rise to a far deeper root system in the resulting plants.<ref name="Palmer-2013" /> This facilitates an improved ability for the rice plant to derive its required nutrients in times of drought via accessing deeper layers of [[soil]], a feature demonstrated by trials which saw the IR64 + DRO1 rice yields drop by 10% under moderate drought conditions, compared to 60% for the unmodified IR64 variety.<ref name="Palmer-2013"/><ref>{{cite web |url=http://phys.org/news/2013-08-roots-breakthrough-drought-resistant-rice.html |title=Roots breakthrough for drought resistant rice |archive-url=https://web.archive.org/web/20131102113839/http://phys.org/news/2013-08-roots-breakthrough-drought-resistant-rice.html |archive-date=November 2, 2013 |work=Phys.org |date=2013 |access-date=September 30, 2013 }}</ref>

=== Salt-tolerance ===

{{further|Crop tolerance to seawater}}

[[Soil salinity]] poses a major threat to rice crop productivity, particularly along low-lying coastal areas during the dry season.<ref name="irri.org"/><ref>{{cite web |work=[[International Rice Research Institute]] |title=Rice Breeding Course, Breeding for salt tolerance in rice, on line |url= http://www.knowledgebank.irri.org/ricebreedingcourse/Breeding_for_salt_tolerance.htm |archive-url=https://web.archive.org/web/20170505220950/http://www.knowledgebank.irri.org/ricebreedingcourse/Breeding_for_salt_tolerance.htm |archive-date=May 5, 2017 }}</ref> For example, roughly {{convert|1|e6ha|e6acre|abbr=off}} of the coastal areas of [[Bangladesh]] are affected by saline soils.<ref>"{{cite web |url=http://irri.org/index.php?option=com_k2&view=item&id=10379&Itemid=100242&lang=en |title=Less salt, please |archive-url=https://web.archive.org/web/20131101133710/http://irri.org/index.php?option=com_k2&view=item&id=10379&Itemid=100242&lang=en |archive-date= 1 November 2013 |last=Fredenburg |first=P. |date=2007 |access-date=30 September 2013 |publisher=[[International Rice Research Institute]] }}</ref> These high concentrations of salt can severely affect rice plants' [[physiology]], especially during early stages of growth, and as such farmers are often forced to abandon these areas.<ref name="IRRI-2013">"{{cite web |url=https://ricetoday.irri.org/wild-parent-spawns-super-salt-tolerant-rice/ |title=Wild parent spawns super salt tolerant rice | last = Barona-Edna | first = Liz | date = April 15, 2013 | accessdate = January 3, 2024 | work=Rice Today }}</ref>

Progress has been made in developing rice varieties capable of tolerating such conditions; the hybrid created from the cross between the commercial rice variety IR56 and the wild rice species ''Oryza coarctata'' is one example.<ref name="Integrated Breeding Platform (IBP)-2013">"{{cite web |url=https://www.integratedbreeding.net/news/breakthrough-salt-resistant-rice-research-single-baby-rice-plant-may-hold-future-extending-rice |title=Breakthrough in salt-resistant rice research—single baby rice plant may hold the future to extending rice farming |archive-url=https://web.archive.org/web/20131102081913/https://www.integratedbreeding.net/news/breakthrough-salt-resistant-rice-research-single-baby-rice-plant-may-hold-future-extending-rice |archive-date=November 2, 2013 |work=Integrated Breeding Platform (IBP) |date=2013 |access-date=October 6, 2013 }}</ref> ''O. coarctata'' can grow in soils with double the limit of salinity of normal varieties, but does not produce edible rice.<ref name="Integrated Breeding Platform (IBP)-2013"/> Developed by the [[International Rice Research Institute]], the [[Hybrid (biology)|hybrid]] variety utilises specialised leaf glands that remove salt into the atmosphere. It was produced from one successful [[embryo]] out of 34,000 crosses between the two species; this was then [[Backcrossing|backcrossed]] to IR56 with the aim of preserving the genes responsible for salt tolerance that were inherited from ''O. coarctata''.<ref name="IRRI-2013"/>

=== Cold tolerance ===

Rice is sensitive to temperatures below 12C. Sowing takes place once the daily average temperature is reliably above this limit. Average temperatures below that reduce growth; if sustained for over four days, germination and seedling growth are harmed and seedlings may die. In larger plants subjected to cold, rice blast is encouraged, seriously reducing yield. As of 2022, researchers continue to study the mechanisms of chilling tolerance in rice and its genetic basis.<ref name="Li Zhang Chong 2022">{{cite journal | last1=Li | first1=Junhua | last2=Zhang | first2=Zeyong | last3=Chong | first3=Kang | last4=Xu | first4=Yunyuan | title=Chilling tolerance in rice: Past and present | journal=[[Journal of Plant Physiology]] | volume=268 | date=2022 | doi=10.1016/j.jplph.2021.153576 | page=153576| pmid=34875419 | bibcode=2022JPPhy.26853576L }}</ref>

=== Reducing methane emissions ===

Producing rice in [[Paddy field|paddies]] is harmful for the environment due to the release of methane by [[Methanogen|methanogenic bacteria]]. These bacteria live in the anaerobic waterlogged soil, consuming nutrients released by rice roots. Putting the [[barley]] gene ''SUSIBA2'' into rice creates a shift in biomass production from root to shoot, decreasing the methanogen population, and resulting in a reduction of methane emissions of up to 97%. Further, the modification increases the amount of rice grains<!-- by 43%-->.<ref>{{cite journal |last1=Su |first1=J. |last2=Hu |first2=C. |last3=Yan |first3=X. |last4=Jin |first4=Y. |last5=Chen |first5=Z. |last6=Guan |first6=Q. |last7=Wang |first7=Y. |last8=Zhong |first8=D. |last9=Jansson |first9=C. |last10=Wang |first10=F. |last11=Schnürer |first11=A. |last12=Sun |first12=C. |display-authors=5 |title=Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice |journal=[[Nature (journal)|Nature]] |volume=523 |issue=7562 |pages=602–606 |date=July 2015 |pmid=26200336 |doi=10.1038/nature14673 |s2cid=4454200 |bibcode=2015Natur.523..602S }}</ref><ref>{{cite web |last=Gerry |first=C. |title=Feeding the World One Genetically Modified Tomato at a Time: A Scientific Perspective |url=http://sitn.hms.harvard.edu/flash/2015/feeding-the-world/ |publisher=[[Harvard University]] |access-date=September 11, 2015 |date=August 9, 2015 |archive-url=https://web.archive.org/web/20150910164510/http://sitn.hms.harvard.edu/flash/2015/feeding-the-world/ |archive-date=September 10, 2015 |url-status=live}}</ref>

===C4 rice===

'''C4 rice''' is a proposed rice that uses [[C4 photosynthesis]].<ref>{{cite web |title=The C4 Rice Project |url=https://c4rice.com |website=c4rice.com |language=en}}</ref> It is currently in development by the C4 Rice Consortium.<ref>{{Cite journal|url=https://www.science.org/doi/10.1126/science.1220177|title=The Development of C4 Rice: Current Progress and Future Challenges|first1=Susanne|last1=von Caemmerer|first2=W. Paul|last2=Quick|first3=Robert T.|last3=Furbank|date=June 29, 2012|journal=Science|volume=336|issue=6089|pages=1671–1672|via=science.org (Atypon)|doi=10.1126/science.1220177}}</ref><ref>{{Cite web|url=https://www.smithsonianmag.com/innovation/is-hacking-photosynthesis-the-key-to-increasing-crop-yields-180981144/|title=Is Hacking Photosynthesis the Key to Increasing Crop Yields?|first=Kurt|last=Kleiner|website=Smithsonian Magazine}}</ref>

=== Model organism ===

Rice is used as a [[model organism]] for investigating the mechanisms of [[meiosis]] and [[DNA repair]] in higher plants.<ref>{{cite journal |last1=Luo |first1=Qiong |last2=Li |first2=Yafei |last3=Shen |first3=Yi |last4=Cheng |first4=Zhukuan |title=Ten years of gene discovery for meiotic event control in rice |journal=[[Journal of Genetics and Genomics]] |volume=41 |issue=3 |pages=125–137 |date=March 2014 |pmid=24656233 |doi=10.1016/j.jgg.2014.02.002 |doi-access=free }}</ref> For example, study using rice has shown that the gene ''OsRAD51C'' is necessary for the accurate repair of DNA double-strand breaks during meiosis.<ref>{{cite journal |last1=Tang |first1=Ding |last2=Miao |first2=Chunbo |last3=Li |first3=Yafei |last4=Wang |first4=Hongjun |last5=Liu |first5=Xiaofei |last6=Yu |first6=Hengxiu |last7=Cheng |first7=Zhukuan |title=OsRAD51C is essential for double-strand break repair in rice meiosis |journal=[[Frontiers in Plant Science]] |volume=5 |page=167 |year=2014 |pmid=24847337 |pmc=4019848 |doi=10.3389/fpls.2014.00167 |doi-access=free }}</ref>

{{Anchor|Culture}}