袁隆平 三系法杂交水稻育种技术

choi

So far I could not comprehend what Yuan did. The announcement of his death prompted me to do it.

(1) Lin Shih-cheng and Yuan Long-ping, Hybrid Rice Breeding in China. In Innovative Approaches to Rice Breeding; Selected papers from the 1979 International Rice Research Conference. Manila: International Rice Research Institute (1980), 35, 35-36 .
https://books.irri.org/9711040018_content.pdf
("The hybrid rice research program in China was initiated in 1964. Within two years, visual inspection of the panicles during the heading stage revealed several male sterile (MS) rice plants in the fields. These MS plants could be classified into three types: pollen free, pollen abortive, and anther degenerative. * * * Unfortunately, all three types of male sterility were controlled by the recessive nucleus genes. No satisfactory maintainers could be found * * * In the autumn of 1970, a MS wild rice plant was found in nature and was named wild abortive (WA). Its discovery was a breakthrough in hybrid rice breeding. * * * WA designates a MS wild rice plant with abortive pollens. It was found by our co-worker, Li Bi-Hu, in a population of common wild rice (Oryza sativa L. f. spontanea) on Hainan island. WA is a typical photoperiod-sensitive plant * * * But its [WA's] sterility is unstable. At temperatures higher than 30°C, some anthers may bear normal pollens, and consequently a few selfed seeds may be produced")

Note:
(a) Lin Shih-cheng  林世成 (1918-1997; born in 福州市, lived entire life in China, and died in Beijing; his birth might explain English spelling of his given name)
(b) English dictionary:
(i) panicle (n; First Known Use 1577; from Latin pānicula, diminutive of [noun masculine] pānus [ear of millet]): "a compound racemose inflorescence   — see INFLORESCENCE ILLUSTRATION"
https://www.merriam-webster.com/dictionary/panicle
(A) When you click "INFLORESCENCE ILLUSTRATION," you see 8 panicle, but also heed 1 raceme. Raceme is a noun and  racemose, its corresponding adjective. Then you understand compound raceme. The "compound racemose inflorescence" has racemose to modify inflorescence.
(B) For rice inflorescence, see Gao X-Q et al, Architecture of Wheat Inflorescence: Insights from Rice. Trends in Plant Science, 24: 802  Xin-Qi Gao Ning Wang Xiu-Ling Wang Xian Sheng Zhang Published:June 27, 2019
https://www.cell.com/trends/plant-science/fulltext/S1360-1385(19)30145-1
https://www.researchgate.net/pro ... ights-from-Rice.pdf
(Fig 1: diagram of rice and wheat inflorescences, side by side)
(ii) The noun inflorescence is 花序 in Taiwan.
(iii) florescence (n; Did You Know?: Latin noun masculine flōs flower)
https://www.merriam-webster.com/dictionary/florescence
(c) Wild Abortive  野败   (A mutation must be named somehow.)
(d) Li Bi-Hu  李必湖 (male)
(e) The genus name of rice (Oryza sativa) is from Latin noun feminine oryza rice.
https://en.wiktionary.org/wiki/oryza
, and species name sativa, from Latin adjective masculine satīvus (feminine satīva) sowed, planted.
https://en.wiktionary.org/wiki/sativus

Oryza
https://www.merriam-webster.com/dictionary/Oryza
(pronunciation: the second syllable is pronounced same as rye)


(2) The mitochondrial gene WA352 accounts for rice mutation Wild Abortive.
(a) Ma H, A Battle Between Genomes in Plant Male Fertility. Nature Genetics, 45: 472 (2013)
https://www.nature.com/articles/ng.2618
(b) Luo D et al, A Detrimental Mitochondrial-Nuclear Interaction Causes Cytoplasmic Male Sterility in Rice. Nature Genetics, 45: 573 (2013)
https://www.nature.com/articles/ng.2570
https://www.researchgate.net/pub ... e_sterility_in_rice

Quote:

(i) Abstract: "Here we report that a new mitochondrial gene, WA352 * * * WA352 accumulates preferentially in the anther tapetum, thereby inhibiting COX11 function in peroxide metabolism and triggering premature tapetal programmed cell death and consequent pollen abortion. WA352-induced sterility can be suppressed by two restorer-of-fertility (Rf) genes, suggesting the existence of different mechanisms [which remain elusive to date] to counteract deleterious cytoplasmic factors.

(ii) text:

"In hybrid crop breeding, crossing different inbred lines produces F1 hybrids that usually have higher yields than the parents, a phenomenon known as hybrid vigor or heterosis.

read the following together with viewing Fig 1(a): The authors found "a previously unidentified ORF [acronym for open reading frame, which means a gene encoding a protein] downstream of rpl5 [a gene encoding No 5 of ribosomal proteins in large subunit; a ribosome is made of a a small subunit and a large subunit] comprising three rice mitochondrial genomic segments and one segment of unknown origin (Fig 1a). The 5' region (512 bp [base pairs]) of this ORF is identical to that of a predicted rice mitochondrial ORF, orf284, whereas the 3' region (583 bp) of the ORF is highly similar to that of another predicted rice mitochondrial ORF, orf288; these characteristics suggest that this recombinant structure evolved recently. This chimeric ORF encodes a 352-residue putative protein [ie, the mitochondrial gene WA352 makes a protein of 352 amino acids] with three transmembrane segments (Supplementary Fig 1b [not reproduced in this Web page]) and was thus named WA352 (Wild Abortive 352). * * * WA352 has no similarity to * * * known genes. [In Fig 1(b), a viable pollen is dark brown to black in color whereas rice mutants with WA352 created transparent/ hollow/ inviable pollen.

"CMS-WA can be restored  by  either  of  two  dominant Rf genes, Rf3 or Rf4 * * * located on chromosomes 1 and 10, respectively [citing two previous reports]. We examined how the Rf genes affect WA352 expression * * *  In the Rf4-carrying lines, the amounts of the WA352 * * * transcripts were decreased to ~20–25% of those [without a functional Rf4 gene]"  at page 574.

"To trace  its origin, we examined WA352 in 17 wild rice  species * * * WA352 probably arose 0.7–2 million years  ago in an ancestor of O rufipogon * * * The maintenance of WA352 in these species during evolution might be attributed to the widespread presence of Rf gene(s) * * *" at page 576 (while on this page, please also view Fig 4(f) ).

Note:
(i) The article in (2)(a) is not available for free, whose figure, however, is reproduced in

Topic 21.4 The Molecular Mechanism of Cytoplasmic Sterility in Rice. In Taiz L et al, Plant Physiology and Development. 6th ed. Sinauer Associates (an imprint of Oxford Univ Press) (2014).
http://6e.plantphys.net/topic21.04.html

Fig 21.4.A's caption read in part: "Center, the cytoplasmic male sterile (CMS) WA cytoplasm has a rearranged mitochondrial genome, resulting in the production of the WA352 protein, which inhibits OsCOX11 function, resulting in male sterility [through premature programmed cell death in the anther tapetum (without nutritional support, pollens die in infancy)]."
(ii) anther (n; History and Etymology for anther: Ultimately from Ancient Greek [noun neuter] anthos flower)
https://en.wiktionary.org/wiki/ἄνθος):
"— see FLOWER ILLUSTRATION"
https://www.merriam-webster.com/dictionary/anther
(iii) tapetum
https://en.wikipedia.org/wiki/Tapetum
(can refer to tapetum (botany) )

Click "tapetum botany" and one sees the diagram of an anther, which is cylindrical. Why cylindrical? Because that is what an anther (at least in rice) looks like. See ***
(c) Wang X et al, Crystal Structure of WA352 Provides Insight into Cytoplasmic Male Sterility in Rice. Biochemical and Biophysical Research Communications, 501: 898 (2018)
https://pubmed.ncbi.nlm.nih.gov/29775612/
("we report the crystal structure of the C-terminal functional domain of WA352 at 1.3 Å resolution. This functional domain, consisting of five α helices, is spindle-shaped with a length of 42 Å, and a diameter of 28 Å. Notably, the absence of any structural similarity to a known protein structure suggests that the WA352 functional domain is a novel fold")

The report is placed behind paywall. However, authors of the report also deposited their 3-D structure:
5ZT3; Crystal structure of WA352 from Oryza sativa. Protein Data Bank (PDB), Research Collaboratory for Structural Bioinformatics (RCSB, which is jointly run by Rutgers University and UC San Francisco and funded by US grants), May 2018,
https://www.rcsb.org/structure/5ZT3

choi

(3) There are two Restorer of Fertility genes, of which Rf4 is cloned but not Rf3. Cloning of Rf4 was reported in
(a) Tang H et al, The Rice Restorer Rf4 for Wild-Abortive Cytoplasmic Male Sterility Encodes a Mitochondrial-Localized PPR Protein that Functions in Reduction of WA352 transcripts. Molecular Plant 7: 1497 (September 2014)
https://www.cell.com/molecular-plant/fulltext/S1674-2052(14)60953-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1674205214609539%3Fshowall%3Dtrue
(Rf4 gene encodes a protein of "18 PPR motifs")

Note:
(i) Latin-English dictionary:
* triginta (numeral): "thirty"
https://en.wiktionary.org/wiki/triginta
(ii) Manna S, An Overview of Pentatricopeptide Repeat Proteins and Their Applications. Biochimie, 113: 93 (2015)
https://www.sciencedirect.com/sc ... i/S030090841500108X

View only the figure: Pentatricopeptide repeat protein (ie, proteins with pentatricopeptide repeats) appear in plants only. Each pentatricopeptide repeat consists of 35 amino acids arranged in two helixes (red and purple), linked by a black rope (made up of amino acids also). The text immediately before the figure said, "The series of helix-turn-helix motifs formed by PPR motifs throughout the protein produces a superhelix with a central groove that allows the protein to bind RNA."  The "superhelix" alludes to numerous PPP repeats forms, in turn, a helix -- with purple columns on one arc of the super column and red columns on the other arc.  
(b) This report was published, somewhat unfortunately, four months later, on the same finding. However, this report explained why normal rice seeds look black. See second quotation in (2)(b)(ii) above.

Kazama T and Toriyama K, A Fertility Restorer Gene, Rf4, Widely Used for Hybrid Rice Breeding Encodes a Pentatricopeptide Repeat Protein. Rice, 7: 28 (December 2014)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4884050/#CR20
("The anthers of WA-CMS are milky white, slender, and stunted * * * and contain shrunken pollen grains lacking starch accumulation ability, because of which they are not stained with 1% potassium iodide [which turns starch blue] (Figure 2a). In contrast, anthers of fertile Taichung 65 are yellow and engorged and contain darkly stained pollen grains")

(4) A detour or perspective: Look at the flowers and you can imagine how 袁隆平 or 李必湖 identified male sterility in the field.

Celine Caseys, The Battle of the Sexes: The Gene That Female-Sterilizes Kiwifruit Flowers. Medium.com, Apr 11, 2018
https://medium.com/plant-cell-ex ... lowers-13d4c9aab20c
("An organism with both male and female reproductive organs, a hermaphrodite, seems unusual. This may read as a shocking fact but most flowers are hermaphrodites. * * * Flowering plants with distinct sexes (male and female on different plants) are super rare. It happens in approximately 5% of all flowering plants. It probably evolved independently in various plant families. * * * If you wonder whether the plants you eat have distinct sexes: asparagus, pistachio, papaya, persimmon, and kiwifruits [Heed Kiwi, which the rest of this blog talked about] all have distinct sexes. Most of the other fruits and veggies you eat are yummy hermaphrodites. What Makes a Male Flower in Kiwifruit? [sectional heading]")

Note:
(a) A plant evolutionary biologist and citizen of Switzerland, Celine Caseys is currently a postdoctoral fellow at UC Davis.
(b) This blog is about

Akahi T et al, A Y-Encoded Suppressor of Feminization Arose via Lineage-Specific Duplication of a Cytokinin Response Regulator in Kiwifruit. Plant Cell, 30: 780 (2018)
https://academic.oup.com/plcell/article/30/4/780/6099033
("one Y-specific locus encoding a type-C cytokinin response regulator, which was called SyGI [by these authors], stood out as being fully male-specific and expressed in developing male flowers, specifically in developing carpels [and caused carpels to wilt] (Figure 3). * * * SyGI playing the role of a female-suppressor gene")
(i) The Japanese surname Akagi may have kanji 赤城 or 赤木.
(ii) In the Flower Illustration found in
flower
https://www.merriam-webster.com/dictionary/flower
, the "pistil" (from Latin noun neuter pistillum pestle) is also known as "carpel" (from Ancient Greek noun masculine karpos fruit).

(c) The blog has a more sophisticated cousin for academics that functioned as a herald to the research report -- much like (2)(a) to (2)(b) above -- and that you need not read:

Celine Caseys, Shy Girl Gives Kiwifruit Male Flowers. Plant Cell, 30: 739 (2018)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5969281/

(d) Hermaphrodite
https://en.wikipedia.org/wiki/Hermaphrodite
(section 1 Etymology)

choi

(5) rice floret:
(a) Thomas L Rost, Rice Anatomy: Flowers. Section of Plant Biology, Division of Biological Sciences, University of California, Davis, undated
https://labs.plb.ucdavis.edu/ros ... /flower/flower.html

Quote:

"The rice 'flower' is called a SPIKELET [which is incorrect. See (b) immediately below; should floret].

"Stamen[:]
• There are 6 stamens in each rice flower.
• Each stamen is composed of an anther and a filament.
• An anther includes 4 elongated sacs where pollen grains are stored.
* * * "

"Carpel[:]
• The carpel consists of  the female parts of the rice flower--the stigma, the style, and the ovary.
* * *"
(b) Grass Disseminules Explained. Identification Tool to Weed Disseminules of California Central Valley Table Grape Production Area, undated
http://idtools.org/id/table_grap ... assDisseminules.htm

Note:
(i) View Figure 1 and text immediately above.
(ii) English dictionary:
* caryopsis (n; Early 19th century from modern Latin, from [Ancient] Greek karuon nut + opsis appearance)
https://www.lexico.com/en/definition/caryopsis
* palea (n, etymology)https://www.lexico.com/en/definition/palea
* lemma (n; from Ancient Greek of identical spelling)
https://en.wiktionary.org/wiki/lemma#Etymology_2
* glume (n; etymology)
https://www.lexico.com/en/definition/glume
(c) Nadie S et al, An Overview on Reproductive Isolation in Oryza sativa Complex. AoB Plants
https://academic.oup.com/aobpla/article/10/6/ply060/5199412
("Reproductive isolation [including but not limited to self-pollination 自花授粉 in rice] is generally regarded as the essence of the speciation process. * * * the present review is restricted to the species and subspecies of the Oryza sativa complex, which includes the two domestic rice cultivars [or subspecies: indica (meaning india; of long grain) and japonica (short grain)] and six wild species")

Note:
(i) AoB Plants was an open-access journal (meaning one reads without fee) founded in 2009 by the Annals of Botany Company, an educational charity based in London.
(ii) View only graphs and a table. Figure 1 mentioned O rufipogon.
(A) Oryza rufipogon. Flora of North America, undated
http://beta.floranorthamerica.org/Oryza_rufipogon  
("Common name: Red rice, Vrownbeard rice. * * * Caryopses 5-7 mm long, 2.2-2.7 mm wide, broadly elliptic or oblong, reddish-brown to dark red")

Despite the name of the web site, O rufipogon "is native to East, South and Southeast Asia." It is 2 meters tall (and remember Green Revolution, which sought out cereal plant with show stem, so that more energy can be stored in grains, rather than spent on stem elongation).   
(B) rufipogon
https://en.wiktionary.org/wiki/rufipogon

Look at a grain in images.google.com for O rufipogon, and you will realize why it is so named.
(ii) Table 1 shows the difference between a wild rice and domesticated rice. It is helpful to consult Figure 3 right below.


(6) Cao L 曹立勇 and Zhan X, Chinese Experiences in Breeding Three-Line, Two-Line and Super Hybrid Rice. In Yan W (ed), Rice; Germplasm, genetics and improvement. IntechOpen (2014)
https://www.intechopen.com/books ... d-super-hybrid-rice
("the difficulty for rice [and wheat] to be a strictly self-pollinated crop unlike corn [and rye] * * * Three-line hybrid system includes the CMS line (A), maintainer line (B) and restorer line (R) for a commercial production of rice hybrids. The A line cannot produce viable pollen due to the interaction between cytoplasmic and nuclear genes, so called cytoplasmic male sterile, which anthers are pale or white and shriveled. The A line is used as a female parent for hybrid seed production, so it is commonly called the CMS line and the seed parent as well. Because the CMS line is male sterile, it cannot be self-reproduced and has to have a maintainer. The B line is the maintainer line, which morphology is highly similar to its corresponding CMS line except its reproductive function. The B line has viable pollen grains and normal seed setting, so can pollinate the A line and the F1 plants from this pollination are male sterile, again. In this way, the male sterility of the A line is maintained, and the A line is reproduced for further use or commercial use in a large scale. Similarly, the R line has viable pollen grains and normal seed setting and can pollinate the A line. Differently from the pollination with B line, the F1 plants from the pollination with R line are highly fertile, or the male sterility of the A line is restored into fertility by R line in their progeny. Therefore, the R line also called the pollen parent, male parent, and/or restoring line")

Note: In order to cultivate large-scale planting hybrid rice, XMS line is imperative; human labor can not individually pollinate rice florets, which is closed to insect pollinators.  


(7)
(a) I question hybrid vigor or heterosis. There is no control for an experiment to show it, and the intellectual/ theoretical foundation, judging from Gregor Mendel's experiments.
(b) Besides, the problem in Taiwan has been too much rice. That is why Taiwan never thinks about rice hybrid.