plant infertility

Summary

Summary: The failure of PLANTS to complete fertilization and obtain seed (SEEDS) as a result of defective POLLEN or ovules, or other aberrations. (Dict. of Plant Genet. and Mol. Biol., 1998)

Top Publications

  1. Engelke T, Hirsche J, Roitsch T. Anther-specific carbohydrate supply and restoration of metabolically engineered male sterility. J Exp Bot. 2010;61:2693-706 pubmed publisher
    ..These findings provide a helpful orientation to classify corresponding candidate genes in further plant species, in addition to the species analysed so far (Arabidopsis, tobacco, tomato, potato, carrots, rice, and wheat). ..
  2. Yang J, Zhang M, Yu J. Relationship between cytoplasmic male sterility and SPL-like gene expression in stem mustard. Physiol Plant. 2008;133:426-34 pubmed publisher
    ..Thereby, we suggest that a probable pathway responsible for CMS in stem mustard involves mitochondrial retrograde regulation, with SPL-like as a target nuclear gene for a mitochondrial signal...
  3. Gabay Laughnan S, Kuzmin E, Monroe J, Roark L, Newton K. Characterization of a novel thermosensitive restorer of fertility for cytoplasmic male sterility in maize. Genetics. 2009;182:91-103 pubmed publisher
    ..The 1.6-kb RNA, which is transcribed only from linear ends, is correspondingly reduced. ..
  4. Ashutosh -, Kumar P, Dinesh Kumar V, Sharma P, Prakash S, Bhat S. A novel orf108 co-transcribed with the atpA gene is associated with cytoplasmic male sterility in Brassica juncea carrying Moricandia arvensis cytoplasm. Plant Cell Physiol. 2008;49:284-9 pubmed publisher
    ..A novel orf108 (open reading frame 108) co-transcribed with the atpA gene was found in the male sterile flowers. In the fertility restorer line, the transcript was cleaved within orf108 to yield monocistronic atpA transcripts...
  5. Zhu Y, Dun X, Zhou Z, Xia S, Yi B, Wen J, et al. A separation defect of tapetum cells and microspore mother cells results in male sterility in Brassica napus: the role of abscisic acid in early anther development. Plant Mol Biol. 2010;72:111-23 pubmed publisher
    ..The REGMS phenotype could be controlled by a primary pathway of male sterile metabolism positively regulated by the BnMs3 gene and a supplementary pathway negatively regulated by the BnRf gene. ..
  6. Bomblies K, Weigel D. Hybrid necrosis: autoimmunity as a potential gene-flow barrier in plant species. Nat Rev Genet. 2007;8:382-93 pubmed
    ..We survey the extensive literature on this topic and present the hypothesis that hybrid necrosis can result from autoimmunity, perhaps as a pleiotropic effect of evolution of genes that are involved in pathogen response. ..
  7. Liu H, Cui P, Zhan K, Lin Q, Zhuo G, Guo X, et al. Comparative analysis of mitochondrial genomes between a wheat K-type cytoplasmic male sterility (CMS) line and its maintainer line. BMC Genomics. 2011;12:163 pubmed publisher
    ..Comparative analysis of several angiosperm mtDNAs indicated that non-coding sequences are the most frequently reorganized during mtDNA evolution in higher plants. ..
  8. Chase C. Cytoplasmic male sterility: a window to the world of plant mitochondrial-nuclear interactions. Trends Genet. 2007;23:81-90 pubmed
    ..The molecular cloning of nuclear genes that restore fertility (i.e. restorer-of-fertility genes) has identified genes encoding pentatricopeptide-repeat proteins as key regulators of plant mitochondrial gene expression. ..
  9. Thévenin J, Pollet B, Letarnec B, Saulnier L, Gissot L, Maia Grondard A, et al. The simultaneous repression of CCR and CAD, two enzymes of the lignin biosynthetic pathway, results in sterility and dwarfism in Arabidopsis thaliana. Mol Plant. 2011;4:70-82 pubmed publisher
    ..These consequences must be carefully considered when trying to reduce the lignin content of plants in order to facilitate the lignocellulose-to-bioethanol conversion process. ..

More Information

Publications62

  1. Yang J, Liu X, Yang X, Zhang M. Mitochondrially-targeted expression of a cytoplasmic male sterility-associated orf220 gene causes male sterility in Brassica juncea. BMC Plant Biol. 2010;10:231 pubmed publisher
  2. Stumpe M, Gobel C, Faltin B, Beike A, Hause B, Himmelsbach K, et al. The moss Physcomitrella patens contains cyclopentenones but no jasmonates: mutations in allene oxide cyclase lead to reduced fertility and altered sporophyte morphology. New Phytol. 2010;188:740-9 pubmed publisher
    ..Targeted knockout mutants for PpAOC1 and for PpAOC2 were generated, while double mutants could not be obtained. The ?PpAOC1 and ?PpAOC2 mutants showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis. ..
  3. Feng X, Kaur A, Mackenzie S, Dweikat I. Substoichiometric shifting in the fertility reversion of cytoplasmic male sterile pearl millet. Theor Appl Genet. 2009;118:1361-70 pubmed publisher
    ..This study furthers the argument that substoichiometric shifting within the plant mitochondrial genome plays an important role in the evolution of the mitochondrial genome and plant reproductive dynamics. ..
  4. Carlsson J, Leino M, Sohlberg J, Sundstrom J, Glimelius K. Mitochondrial regulation of flower development. Mitochondrion. 2008;8:74-86 pubmed
    ..Here, we review the mitochondrial influence on flower development and give examples from CMS-systems developed in Brassica, Daucus carota, Nicotiana tabacum and Triticum aestivum. ..
  5. Satoh M, Kubo T, Mikami T. The Owen mitochondrial genome in sugar beet (Beta vulgaris L.): possible mechanisms of extensive rearrangements and the origin of the mitotype-unique regions. Theor Appl Genet. 2006;113:477-84 pubmed
    ..This suggests that, in addition to the incorporation of foreign DNAs, extensive duplication of short repetitive sequences and continued scrambling of mtDNA sequences may be implicated in the generation of the Owen CMS-unique regions. ..
  6. Chen Y, Lei S, Zhou Z, Zeng F, Yi B, Wen J, et al. Analysis of gene expression profile in pollen development of recessive genic male sterile Brassica napus L. line S45A. Plant Cell Rep. 2009;28:1363-72 pubmed publisher
    ..The role of Bnms1 in the regulatory network of exine formation is also discussed as well. ..
  7. Schmitz Linneweber C, Small I. Pentatricopeptide repeat proteins: a socket set for organelle gene expression. Trends Plant Sci. 2008;13:663-70 pubmed publisher
    ..We use these new data to propose hypotheses for their physiological roles that could explain why PPR proteins are so numerous in terrestrial plants. ..
  8. Case A, Willis J. Hybrid male sterility in Mimulus (Phrymaceae) is associated with a geographically restricted mitochondrial rearrangement. Evolution. 2008;62:1026-39 pubmed publisher
    ..Extreme localization may be characteristic of CMS in hermaphroditic species, in contrast to geographically widespread mitotypes commonly found in gynodioecious species, and could directly contribute to hybrid incompatibilities in nature...
  9. Xu J, Yang C, Yuan Z, Zhang D, Gondwe M, Ding Z, et al. The ABORTED MICROSPORES regulatory network is required for postmeiotic male reproductive development in Arabidopsis thaliana. Plant Cell. 2010;22:91-107 pubmed publisher
    ..These results provide insight into the regulatory role of the AMS network during anther development. ..
  10. Uyttewaal M, Arnal N, Quadrado M, Martin Canadell A, Vrielynck N, Hiard S, et al. Characterization of Raphanus sativus pentatricopeptide repeat proteins encoded by the fertility restorer locus for Ogura cytoplasmic male sterility. Plant Cell. 2008;20:3331-45 pubmed publisher
    ..Together, our data support a role for PPR-B in the translational regulation of orf138 mRNA...
  11. Yang S, Terachi T, Yamagishi H. Inhibition of chalcone synthase expression in anthers of Raphanus sativus with Ogura male sterile cytoplasm. Ann Bot. 2008;102:483-9 pubmed publisher
    ..These results show that flavonoids play an important role in the development of functional pollen, not only in nuclear-dependent male sterility, but also in CMS...
  12. Jung K, Han M, Lee Y, Kim Y, Hwang I, Kim M, et al. Rice Undeveloped Tapetum1 is a major regulator of early tapetum development. Plant Cell. 2005;17:2705-22 pubmed
    ..DNA microarray analysis identified 958 downregulated and 267 upregulated genes in the udt1-1 anthers, suggesting that Udt1 plays a major role in maintaining tapetum development, starting in early meiosis. ..
  13. Das S, Sen S, Chakraborty A, Chakraborti P, Maiti M, Basu A, et al. An unedited 1.1 kb mitochondrial orfB gene transcript in the wild abortive cytoplasmic male sterility (WA-CMS) system of Oryza sativa L. subsp. indica. BMC Plant Biol. 2010;10:39 pubmed publisher
    ..A new point of departure to dissect the mechanisms governing the CMS-WA system in rice has been identified, which can be applied to further harness the opportunities afforded by hybrid vigor in rice...
  14. Jing B, Heng S, Tong D, Wan Z, Fu T, Tu J, et al. A male sterility-associated cytotoxic protein ORF288 in Brassica juncea causes aborted pollen development. J Exp Bot. 2012;63:1285-95 pubmed publisher
    ..These observations provide important evidence that orf288 is responsible for the male sterility of hau CMS in Brassica juncea. ..
  15. Dong X, Kim W, Lim Y, Kim Y, Hur Y. Ogura-CMS in Chinese cabbage (Brassica rapa ssp. pekinensis) causes delayed expression of many nuclear genes. Plant Sci. 2013;199-200:7-17 pubmed publisher
    ..Delayed expression may reduce pollen grain production and/or cause sterility, implying that mitochondrial, retrograde signaling delays nuclear gene expression...
  16. Moyle L, Nakazato T. Comparative genetics of hybrid incompatibility: sterility in two Solanum species crosses. Genetics. 2008;179:1437-53 pubmed publisher
    ..We show that comparative mapping data can delimit the probable timing of evolution of detected QTL and discern which sterility loci likely evolved earliest among species. ..
  17. Jung K, Han M, Lee D, Lee Y, Schreiber L, Franke R, et al. Wax-deficient anther1 is involved in cuticle and wax production in rice anther walls and is required for pollen development. Plant Cell. 2006;18:3015-32 pubmed
    ..Our findings provide new insights into the biochemical and developmental aspects of the role of waxes in microspore exine development in the tapetum as well as the role of epicuticular waxes in anther expansion. ..
  18. Ito T, Nagata N, Yoshiba Y, Ohme Takagi M, Ma H, Shinozaki K. Arabidopsis MALE STERILITY1 encodes a PHD-type transcription factor and regulates pollen and tapetum development. Plant Cell. 2007;19:3549-62 pubmed
    ..From these results, we discuss a role of MS1 in pollen and tapetum development and the conservation of MS1 function in flowering plants. ..
  19. Xu P, Yang Y, Zhang Z, Chen W, Zhang C, Zhang L, et al. Expression of the nuclear gene TaF(A)d is under mitochondrial retrograde regulation in anthers of male sterile wheat plants with timopheevii cytoplasm. J Exp Bot. 2008;59:1375-81 pubmed publisher
    ..These observations implied that TaF(A)d is under mitochondrial retrograde regulation in the anthers of CMS plants with timopheevii cytoplasm...
  20. Long Y, Zhao L, Niu B, Su J, Wu H, Chen Y, et al. Hybrid male sterility in rice controlled by interaction between divergent alleles of two adjacent genes. Proc Natl Acad Sci U S A. 2008;105:18871-6 pubmed publisher
    ..We propose a two-gene/three-component interaction model for this hybrid male sterility system. The findings have implications for overcoming male sterility in inter-subspecific hybrid rice breeding. ..
  21. Itabashi E, Kazama T, Toriyama K. Characterization of cytoplasmic male sterility of rice with Lead Rice cytoplasm in comparison with that with Chinsurah Boro II cytoplasm. Plant Cell Rep. 2009;28:233-9 pubmed publisher
    ..These results suggest that accumulation of ORF79 is not the cause of CMS in LD-cytoplasm and the mechanism of male-sterility induction/fertility restoration in LD-CMS is different from that in BT-CMS. ..
  22. Yang J, Huai Y, Zhang M. Mitochondrial atpA gene is altered in a new orf220-type cytoplasmic male-sterile line of stem mustard (Brassica juncea). Mol Biol Rep. 2009;36:273-80 pubmed
    ..Therefore, we deduced that mitochondrial atpA gene altered in cms could be associated with male-sterility in this type of cms...
  23. Shi Y, Zhao S, Yao J. Premature tapetum degeneration: a major cause of abortive pollen development in photoperiod sensitive genic male sterility in rice. J Integr Plant Biol. 2009;51:774-81 pubmed publisher
  24. Villarreal F, Martin V, Colaneri A, González Schain N, Perales M, Martin M, et al. Ectopic expression of mitochondrial gamma carbonic anhydrase 2 causes male sterility by anther indehiscence. Plant Mol Biol. 2009;70:471-85 pubmed publisher
    ..We propose that reduction in ROS inhibits H(2)O(2) dependent lignin polymerization in CA2 over-expressing plants, thereby causing male sterility. ..
  25. Yamamoto M, Shinada H, Onodera Y, Komaki C, Mikami T, Kubo T. A male sterility-associated mitochondrial protein in wild beets causes pollen disruption in transgenic plants. Plant J. 2008;54:1027-36 pubmed publisher
    ..Transgenic expression of ORF129 resulted in male sterility, which provides clear supporting evidence that ORF129 is responsible for the male-sterile phenotype in sugar beet with wild beet cytoplasm. ..
  26. Song S, Qi T, Huang H, Ren Q, Wu D, Chang C, et al. The Jasmonate-ZIM domain proteins interact with the R2R3-MYB transcription factors MYB21 and MYB24 to affect Jasmonate-regulated stamen development in Arabidopsis. Plant Cell. 2011;23:1000-13 pubmed publisher
  27. Gardner N, Felsheim R, Smith A. Production of male- and female-sterile plants through reproductive tissue ablation. J Plant Physiol. 2009;166:871-81 pubmed publisher
    ..The combination of male- and female-sterility genes was effective in eliminating seed set in all the lines examined and has direct application for reducing invasiveness of ornamental plants. ..
  28. Carlsson J, Lagercrantz U, Sundström J, Teixeira R, Wellmer F, Meyerowitz E, et al. Microarray analysis reveals altered expression of a large number of nuclear genes in developing cytoplasmic male sterile Brassica napus flowers. Plant J. 2007;49:452-62 pubmed
    ..These results suggest that AP3 expression in stamens depends on proper mt function and a correct nuclear-mt interaction, and that mt alterations cause the male sterility phenotype of the CMS line. ..
  29. Ogawa M, Kay P, Wilson S, Swain S. ARABIDOPSIS DEHISCENCE ZONE POLYGALACTURONASE1 (ADPG1), ADPG2, and QUARTET2 are Polygalacturonases required for cell separation during reproductive development in Arabidopsis. Plant Cell. 2009;21:216-33 pubmed publisher
    ..These results demonstrate that multiple cell separation events, including both abscission and dehiscence, require closely related PG genes. ..
  30. Fujii S, Toriyama K. DCW11, down-regulated gene 11 in CW-type cytoplasmic male sterile rice, encoding mitochondrial protein phosphatase 2c is related to cytoplasmic male sterility. Plant Cell Physiol. 2008;49:633-40 pubmed publisher
    ..Down-regulation of DCW11 and up-regulation of AOX1a were also observed in two other types of rice CMS. Our result indicates that DCW11 could play a role as a mitochondrial signal transduction mediator in pollen germination. ..
  31. Fujii S, Bond C, Small I. Selection patterns on restorer-like genes reveal a conflict between nuclear and mitochondrial genomes throughout angiosperm evolution. Proc Natl Acad Sci U S A. 2011;108:1723-8 pubmed publisher
    ..We suggest that the selection patterns on Rf-like genes reveal a molecular "arms-race" between the nuclear and mitochondrial genomes that has persisted throughout most of the evolutionary history of angiosperms. ..
  32. Wei W, Li Y, Wang L, Liu S, Yan X, Mei D, et al. Development of a novel Sinapis arvensis disomic addition line in Brassica napus containing the restorer gene for Nsa CMS and improved resistance to Sclerotinia sclerotiorum and pod shattering. Theor Appl Genet. 2010;120:1089-97 pubmed publisher
    ..Because the addition line shares these very important agricultural characters, it is a valuable restorer to Nsa CMS line, and is named NR1 here (Nsa restorer no. 1)...
  33. Li X, Gao X, Wei Y, Deng L, Ouyang Y, Chen G, et al. Rice APOPTOSIS INHIBITOR5 coupled with two DEAD-box adenosine 5'-triphosphate-dependent RNA helicases regulates tapetum degeneration. Plant Cell. 2011;23:1416-34 pubmed publisher
    ..Our results uncover a previously unknown pathway for regulating PCD during tapetum degeneration in rice, one that may be conserved among eukaryotic organisms...
  34. Shi S, Ding D, Mei S, Wang J. A comparative light and electron microscopic analysis of microspore and tapetum development in fertile and cytoplasmic male sterile radish. Protoplasma. 2010;241:37-49 pubmed publisher
    ..Thus, the identical factors, which induced CMS in the same cytoplasmic and nuclear genetic background, might affect development of tapetum and microspore at different stages during the cytoplasmic male sterile 805A anther development. ..
  35. Zhang Z, Lu Y, Liu X, Feng J, Zhang G. Cytological mechanism of pollen abortion resulting from allelic interaction of F1 pollen sterility locus in rice (Oryza sativa L.). Genetica. 2006;127:295-302 pubmed
    ..Genotypic identification indicated that the abortive pollen were those with S ( j ) allele. ..
  36. Choi H, Jin J, Choi S, Hwang J, Kim Y, Suh M, et al. An ABCG/WBC-type ABC transporter is essential for transport of sporopollenin precursors for exine formation in developing pollen. Plant J. 2011;65:181-93 pubmed publisher
    ..Taken together, these results suggest that ABCG26 plays a crucial role in the transfer of sporopollenin lipid precursors from tapetal cells to anther locules, facilitating exine formation on the pollen surface...
  37. Suzuki G. Recent progress in plant reproduction research: the story of the male gametophyte through to successful fertilization. Plant Cell Physiol. 2009;50:1857-64 pubmed publisher
    ..We are just beginning to understand the molecular mechanisms of the elaborate reproduction system in flowering plants, which have been a mystery for >100 years. ..
  38. Xing S, Zachgo S. ROXY1 and ROXY2, two Arabidopsis glutaredoxin genes, are required for anther development. Plant J. 2008;53:790-801 pubmed
    ..Analysis of these two novel anther genes indicates that redox regulation, as well as participating in plant stress defense mechanisms, might play a major role in the control of male gametogenesis. ..
  39. González Melendi P, Uyttewaal M, Morcillo C, Hernández Mora J, Fajardo S, Budar F, et al. A light and electron microscopy analysis of the events leading to male sterility in Ogu-INRA CMS of rapeseed (Brassica napus). J Exp Bot. 2008;59:827-38 pubmed publisher
  40. Duroc Y, Hiard S, Vrielynck N, Ragu S, Budar F. The Ogura sterility-inducing protein forms a large complex without interfering with the oxidative phosphorylation components in rapeseed mitochondria. Plant Mol Biol. 2009;70:123-37 pubmed publisher
    ..In vivo respiration measurements suggest that the difference in O(2) consumption measured at the organelle level is compensated at the cell/tissue level, completely in leaves, but only partially in male reproductive organs. ..
  41. Hu J, Wang K, Huang W, Liu G, Gao Y, Wang J, et al. The rice pentatricopeptide repeat protein RF5 restores fertility in Hong-Lian cytoplasmic male-sterile lines via a complex with the glycine-rich protein GRP162. Plant Cell. 2012;24:109-22 pubmed publisher
    ..Evidence that a PPR protein interacts directly with a Gly-rich protein to form a subunit of the RFC provides a new perspective on the molecular mechanisms underlying fertility restoration. ..
  42. Fujii S, Toriyama K. Genome barriers between nuclei and mitochondria exemplified by cytoplasmic male sterility. Plant Cell Physiol. 2008;49:1484-94 pubmed publisher
    ..This review summarizes the current perspectives in CMS and fertility restoration, mainly from the viewpoint of anterograde/retrograde signaling. ..
  43. Sweigart A, Fishman L, Willis J. A simple genetic incompatibility causes hybrid male sterility in mimulus. Genetics. 2006;172:2465-79 pubmed
    ..This possibility is supported by our discovery that recombination is reduced dramatically in a cross involving a parent with the hms1-hms2 incompatibility...
  44. Luo D, Xu H, Liu Z, Guo J, Li H, Chen L, et al. A detrimental mitochondrial-nuclear interaction causes cytoplasmic male sterility in rice. Nat Genet. 2013;45:573-7 pubmed publisher
    ..Thus, CMS-related cytoplasmic-nuclear incompatibility is driven by a detrimental interaction between a newly evolved mitochondrial gene and a conserved, essential nuclear gene...
  45. Cheng S, Zhuang J, Fan Y, Du J, Cao L. Progress in research and development on hybrid rice: a super-domesticate in China. Ann Bot. 2007;100:959-66 pubmed
    ..Molecular marker-assisted selection is a powerful tool to increase breeding efficiency, but much work remains to be done before this technique can be extended from major genes to QTLs. ..
  46. Ye Q, Zhu W, Li L, Zhang S, Yin Y, Ma H, et al. Brassinosteroids control male fertility by regulating the expression of key genes involved in Arabidopsis anther and pollen development. Proc Natl Acad Sci U S A. 2010;107:6100-5 pubmed publisher
    ..Our work provides a unique mechanism to explain how a phytohormone regulates an essential genetic program for plant development. ..
  47. Yamagata Y, Yamamoto E, Aya K, Win K, Doi K, Ito T, et al. Mitochondrial gene in the nuclear genome induces reproductive barrier in rice. Proc Natl Acad Sci U S A. 2010;107:1494-9 pubmed publisher
    ..On the basis of these results, we discuss the possible contribution of the "founder effect" in establishing this reproductive barrier...
  48. Lee Y, Kim S, Lim H, Ahn Y, Sung S. Identification of mitochondrial genome rearrangements unique to novel cytoplasmic male sterility in radish (Raphanus sativus L.). Theor Appl Genet. 2009;118:719-28 pubmed publisher
    ..Therefore, this single nucleotide polymorphism (SNP) in the coding sequence of the mtDNA will be a useful molecular marker for the detection of the DCGMS mitotype...
  49. Crawford B, Ditta G, Yanofsky M. The NTT gene is required for transmitting-tract development in carpels of Arabidopsis thaliana. Curr Biol. 2007;17:1101-8 pubmed
    ..This occurs by facilitating pollen-tube growth through differentiation and then death of transmitting-tract cells. ..
  50. Fujii S, Kazama T, Yamada M, Toriyama K. Discovery of global genomic re-organization based on comparison of two newly sequenced rice mitochondrial genomes with cytoplasmic male sterility-related genes. BMC Genomics. 2010;11:209 pubmed publisher
    ..Genomic rearrangements were dynamic in the CMS lines in comparison with those of rice cultivars, suggesting that 'death' and possible 'birth' processes of the CMS genes occurred during the breeding history of rice. ..
  51. Nizampatnam N, Doodhi H, Kalinati Narasimhan Y, Mulpuri S, Viswanathaswamy D. Expression of sunflower cytoplasmic male sterility-associated open reading frame, orfH522 induces male sterility in transgenic tobacco plants. Planta. 2009;229:987-1001 pubmed publisher
    ..This constitutes the first report at demonstrating the induction of male sterility by introducing orfH522 gene that could be useful for genetic engineering of male sterility. ..
  52. He J, Ke L, Hong D, Xie Y, Wang G, Liu P, et al. Fine mapping of a recessive genic male sterility gene (Bnms3) in rapeseed (Brassica napus) with AFLP- and Arabidopsis-derived PCR markers. Theor Appl Genet. 2008;117:11-8 pubmed publisher
    ..56 to 0.14 cM. These results provide additional information for map-based cloning of the Bnms3 gene and will be helpful for marker-assisted selection (MAS) of elite RGMS lines and maintainers. ..
  53. Duroc Y, Gaillard C, Hiard S, Defrance M, Pelletier G, Budar F. Biochemical and functional characterization of ORF138, a mitochondrial protein responsible for Ogura cytoplasmic male sterility in Brassiceae. Biochimie. 2005;87:1089-100 pubmed
    ..The production of this protein strongly inhibited bacterial growth, but not by inhibiting respiration. The observed toxic effects required both the hydrophilic and hydrophobic moieties of the protein. ..