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. 2021 Jun 30;21(1):308.
doi: 10.1186/s12870-021-03109-z.

Dynamic formation and transcriptional regulation mediated by phytohormones during chalkiness formation in rice

Qin Xie #  1   2 , Jinke Xu #  1 , Ke Huang  1 , Yi Su  1   2 , Jianhua Tong  1 , Zhigang Huang  1   2 , Chao Huang  1   2 , Manlin Wei  1 , Wanhuang Lin  3   4 , Langtao Xiao  5   6
Affiliations

Dynamic formation and transcriptional regulation mediated by phytohormones during chalkiness formation in rice

Qin Xie et al. BMC Plant Biol. .

Abstract

Background: Rice (Oryza sativa L.) Chalkiness, the opaque part in the kernel endosperm formed by loosely piled starch and protein bodies. Chalkiness is a complex quantitative trait regulated by multiple genes and various environmental factors. Phytohormones play important roles in the regulation of chalkiness formation but the underlying molecular mechanism is still unclear at present.

Results: In this research, Xiangzaoxian24 (X24, pure line of indica rice with high-chalkiness) and its origin parents Xiangzaoxian11 (X11, female parent, pure line of indica rice with high-chalkiness) and Xiangzaoxian7 (X7, male parent, pure line of indica rice with low-chalkiness) were used as materials. The phenotype, physiological and biochemical traits combined with transcriptome analysis were conducted to illustrate the dynamic process and transcriptional regulation of rice chalkiness formation. Impressively, phytohormonal contents and multiple phytohormonal signals were significantly different in chalky caryopsis, suggesting the involvement of phytohormones, particularly ABA and auxin, in the regulation of rice chalkiness formation, through the interaction of multiple transcription factors and their downstream regulators.

Conclusion: These results indicated that chalkiness formation is a dynamic process associated with multiple genes, forming a complex regulatory network in which phytohormones play important roles. These results provided informative clues for illustrating the regulatory mechanisms of chalkiness formation in rice.

Keywords: Chalkiness; Dynamic formation; Phytohormones; Rice; Transcriptional regulation.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
The phenotype of mature grains (A), chalkiness trait (B), chalky rice rate (C), chalkiness degree (D), grain length (E), grain width (F) and 1000-grains weight (G) of X11, X7 and X24. Data shown as means ± SD of three biological replicates (n = 30). Asterisks indicate a significant difference based on a Dunnett’s test. * significant difference at 5% level (P < 0.05); ** significant difference at 1% level (P < 0.01)
Fig. 2
Fig. 2
The dynamics of grain filling and chalkiness formation traits (A and B). The starch granules in endosperms examined by SEM at 8 DAH, 12 DAH, 16 DAH, 20 DAH and 24 DAH (Scale bars: 10 μm) (C)
Fig. 3
Fig. 3
DEGs obtained by X11 vs. X7, X24 vs. X7 and X11 vs. X24 at (A) 8 DAH, (B) 12 DAH and (C) 16 DAH. Red column represents up-regulated of genes, blue column represents down-regulated of genes. Venn diagram of DEGs among X11, X7 and X24 at (D) 8 DAH, (E) 12 DAH and (F) 16 DAH. DEGs were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 4
Fig. 4
Comparison of Gene Ontology (GO) classifications of DEGs at (A) 8 DAH, (B) 12 DAH and (C) 16 DAH. (D) KEGG pathway assignments of DEGs at 8 DAH, 12 DAH and 16 DAH, the top 10 categories are shown. DEGs were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 5
Fig. 5
A The starch content in of mature grain in X11, X7 and X24. B The starch and soluble protein content in of mature grain in X11, X7 and X24, data shown as means ± SD of three biological replicates, asterisks indicate a significant difference based on a Dunnett’s test. * significant difference at 5% level (P < 0.05); ** significant difference at 1% level (P < 0.01). C DEGHL involved in starch and sucrose metabolism at 8 DAH, 12 DAH and 16 DAH, which are shown as log2Foldchange levels. DEGHL were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 6
Fig. 6
The phytohormonal contents (A) ABA, (B) IAA and (C) ZR at 8 DAH, 12 DAH and 16 DAH, data shown as means ± SD of three biological replicates, asterisks indicate a significant difference based on a Dunnett’s test. * significant difference at 5% level (P < 0.05); ** significant difference at 1% level (P < 0.01). (D) Expression patterns of phytohormone-related DEGHL at 8 DAH, 12 DAH and 16 DAH, which are shown as log2Foldchange levels. DEGHL were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 7
Fig. 7
Expression patterns of DEGHL encoding TFs obtained at 8 DAH, 12 DAH and 16 DAH, which are shown as log2Foldchange levels. DEGHL were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 8
Fig. 8
Expression patterns of DEGHL encoding PKs obtained at 8 DAH, 12 DAH and 16 DAH, which are shown as log2Foldchange levels. DEGHL were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1)
Fig. 9
Fig. 9
Expression patterns of 12 DEGHL confirmed by real-time PCR, which are shown as log2Foldchange levels. DEGHL were differentially expressed with statistical significance (P-value ≤ 0.05 and |Log2foldchange(FC)|≥ 1). Data shown as means ± SD of three biological replicates. Asterisks indicate a significant difference based on a Dunnett’s test. * significant difference at 5% level (P < 0.05); ** significant difference at 1% level (P < 0.01)
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References

    1. Kim SS, Lee SE, Kim OW, Kim DC. Physicochemical characteristics of chalky kernels and their effects on sensory quality of cooked rice. Cereal Chem. 2000;77(3):376–379. doi: 10.1094/CCHEM.2000.77.3.376. - DOI
    1. Ishimaru T, Horigane AK, Ida M, Iwasawa N, San-oh YA, Nakazono M, Nishizawa NK, Masumura T, Kondo M, Yoshida M. Formation of grain chalkiness and changes in water distribution in developing rice caryopses grown under high-temperature stress. J Cereal Sci. 2009;50(2):166–174. doi: 10.1016/j.jcs.2009.04.011. - DOI
    1. Lin Z, Wang Z, Zhang X, Liu Z, Li G, Wang S, Ding Y. Complementary proteome and transcriptome profiling in developing grains of a notched-belly rice mutant reveals key pathways involved in chalkiness formation. Plant Cell Physiol. 2017;58(3):560–573. doi: 10.1093/pcp/pcx001. - DOI - PMC - PubMed
    1. Lin Z, Zheng D, Zhang X, Wang Z, Lei J, Liu Z, Li G, Wang S, Ding Y. Chalky part differs in chemical composition from translucent part of japonica rice grains as revealed by a notched-belly mutant with white-belly. J Sci Food Agric. 2016;96(11):3937–3943. doi: 10.1002/jsfa.7793. - DOI - PMC - PubMed
    1. Zhou L, Chen L, Jiang L, Zhang W, Liu L, Liu X, Zhao Z, Liu S, Zhang L, Wang J, et al. Fine mapping of the grain chalkiness QTL qPGWC-7 in rice (Oryza sativa L.) Theoretical Appl Genet. 2009;118(3):581–590. doi: 10.1007/s00122-008-0922-0. - DOI - PubMed

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