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OsKinesin-13A is an active microtubule depolymerase involved in glume length regulation via affecting cell elongation.

Deng ZY, Liu LT, Li T, Yan S, Kuang BJ, Huang SJ, Yan CJ, Wang T - Sci Rep (2015)

Bottom Line: Consistently, sar1 showed reduced transverse orientation of cortical microtubules.Further observations demonstrated that microtubule turnover was decreased in sar1.Thus, our results suggest that OsKinesin-13A utilizes its microtubule depolymerization activity to promote microtubule turnover, which may not only influence transverse orientation of cortical microtubules but also facilitate vesicle transport from the Golgi apparatus to the cell surface, and thus affects cellulose microfibril orientation and cell elongation.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.

ABSTRACT
Grain size is an important trait influencing both the yield and quality of rice and its major determinant is glume size. However, how glume size is regulated remains largely unknown. Here, we report the characterization of OsKinesin-13A, which regulates cell elongation and glume length in rice. The mutant of OsKinesin-13A, sar1, displayed length reduction in grains and other organs including internodes, leaves and roots. The grain phenotype in sar1 was directly caused by reduction in glume length, which in turn restricted caryopsis size. Histological results revealed that length decrease in sar1 organs resulted from abnormalities in cell elongation. The orientation of cellulose microfibrils was defective in sar1. Consistently, sar1 showed reduced transverse orientation of cortical microtubules. Further observations demonstrated that microtubule turnover was decreased in sar1. OsKinesin-13A was shown to be an active microtubule depolymerase and mainly distributed on vesicles derived from the Golgi apparatus and destined for the cell surface. Thus, our results suggest that OsKinesin-13A utilizes its microtubule depolymerization activity to promote microtubule turnover, which may not only influence transverse orientation of cortical microtubules but also facilitate vesicle transport from the Golgi apparatus to the cell surface, and thus affects cellulose microfibril orientation and cell elongation.

No MeSH data available.


Related in: MedlinePlus

The dynamic instability behavior of individual microtubules is altered in sar1.(A–D) Sequential images from time-lapse movies of WT (A and C) and sar1 (B and D) cells expressing EGFP-tagged α-tubulin. Red arrowheads track the plus ends of selected microtubules. White numbers indicate the elapsed time (seconds). Yellow letter C highlights microtubule catastrophe events (switches from growth to shrinkage). Scale bar = 1 µm in (A) for (A) to (D). See the entire series in Supplemental Movie 1 to 4 that correspond to panel A to D, respectively.
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f6: The dynamic instability behavior of individual microtubules is altered in sar1.(A–D) Sequential images from time-lapse movies of WT (A and C) and sar1 (B and D) cells expressing EGFP-tagged α-tubulin. Red arrowheads track the plus ends of selected microtubules. White numbers indicate the elapsed time (seconds). Yellow letter C highlights microtubule catastrophe events (switches from growth to shrinkage). Scale bar = 1 µm in (A) for (A) to (D). See the entire series in Supplemental Movie 1 to 4 that correspond to panel A to D, respectively.

Mentions: To confirm directly that OsKinesin-13A regulates the turnover of microtubules in vivo, we analyzed the dynamic instability behavior of individual microtubules in WT and sar1 cells that expressing enhanced green fluorescent protein (EGFP)-tagged α-tubulin. In sar1 root cells (Figure 6B and D, Table 3, Supplemental Movie 2 and 4), the microtubule growth rate and catastrophe (the switch from growth to shrinkage) frequency were significantly reduced compared to that in WT (Figure 6A and C, Supplemental Movie 1 and 3). Microtubules in sar1 spent less time in the shrinkage phase but more time in the pause phase (Table 3). Moreover, sar1 displayed an increase in the microtubule shrinkage rate (Table 3). The microtubule rescue (the switch from shrinkage to growth) frequency and the percent of time that microtubules spent in the growth phase seemed not influenced in sar1 (Table 3). Overall, microtubules of sar1 had lower dynamicity than those of WT (Table 3). The changes in the parameters of microtubule dynamic instability in sar1 showed OsKinesin-13A may promote microtubule turnover mainly by stimulating microtubule catastrophe.


OsKinesin-13A is an active microtubule depolymerase involved in glume length regulation via affecting cell elongation.

Deng ZY, Liu LT, Li T, Yan S, Kuang BJ, Huang SJ, Yan CJ, Wang T - Sci Rep (2015)

The dynamic instability behavior of individual microtubules is altered in sar1.(A–D) Sequential images from time-lapse movies of WT (A and C) and sar1 (B and D) cells expressing EGFP-tagged α-tubulin. Red arrowheads track the plus ends of selected microtubules. White numbers indicate the elapsed time (seconds). Yellow letter C highlights microtubule catastrophe events (switches from growth to shrinkage). Scale bar = 1 µm in (A) for (A) to (D). See the entire series in Supplemental Movie 1 to 4 that correspond to panel A to D, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373686&req=5

f6: The dynamic instability behavior of individual microtubules is altered in sar1.(A–D) Sequential images from time-lapse movies of WT (A and C) and sar1 (B and D) cells expressing EGFP-tagged α-tubulin. Red arrowheads track the plus ends of selected microtubules. White numbers indicate the elapsed time (seconds). Yellow letter C highlights microtubule catastrophe events (switches from growth to shrinkage). Scale bar = 1 µm in (A) for (A) to (D). See the entire series in Supplemental Movie 1 to 4 that correspond to panel A to D, respectively.
Mentions: To confirm directly that OsKinesin-13A regulates the turnover of microtubules in vivo, we analyzed the dynamic instability behavior of individual microtubules in WT and sar1 cells that expressing enhanced green fluorescent protein (EGFP)-tagged α-tubulin. In sar1 root cells (Figure 6B and D, Table 3, Supplemental Movie 2 and 4), the microtubule growth rate and catastrophe (the switch from growth to shrinkage) frequency were significantly reduced compared to that in WT (Figure 6A and C, Supplemental Movie 1 and 3). Microtubules in sar1 spent less time in the shrinkage phase but more time in the pause phase (Table 3). Moreover, sar1 displayed an increase in the microtubule shrinkage rate (Table 3). The microtubule rescue (the switch from shrinkage to growth) frequency and the percent of time that microtubules spent in the growth phase seemed not influenced in sar1 (Table 3). Overall, microtubules of sar1 had lower dynamicity than those of WT (Table 3). The changes in the parameters of microtubule dynamic instability in sar1 showed OsKinesin-13A may promote microtubule turnover mainly by stimulating microtubule catastrophe.

Bottom Line: Consistently, sar1 showed reduced transverse orientation of cortical microtubules.Further observations demonstrated that microtubule turnover was decreased in sar1.Thus, our results suggest that OsKinesin-13A utilizes its microtubule depolymerization activity to promote microtubule turnover, which may not only influence transverse orientation of cortical microtubules but also facilitate vesicle transport from the Golgi apparatus to the cell surface, and thus affects cellulose microfibril orientation and cell elongation.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.

ABSTRACT
Grain size is an important trait influencing both the yield and quality of rice and its major determinant is glume size. However, how glume size is regulated remains largely unknown. Here, we report the characterization of OsKinesin-13A, which regulates cell elongation and glume length in rice. The mutant of OsKinesin-13A, sar1, displayed length reduction in grains and other organs including internodes, leaves and roots. The grain phenotype in sar1 was directly caused by reduction in glume length, which in turn restricted caryopsis size. Histological results revealed that length decrease in sar1 organs resulted from abnormalities in cell elongation. The orientation of cellulose microfibrils was defective in sar1. Consistently, sar1 showed reduced transverse orientation of cortical microtubules. Further observations demonstrated that microtubule turnover was decreased in sar1. OsKinesin-13A was shown to be an active microtubule depolymerase and mainly distributed on vesicles derived from the Golgi apparatus and destined for the cell surface. Thus, our results suggest that OsKinesin-13A utilizes its microtubule depolymerization activity to promote microtubule turnover, which may not only influence transverse orientation of cortical microtubules but also facilitate vesicle transport from the Golgi apparatus to the cell surface, and thus affects cellulose microfibril orientation and cell elongation.

No MeSH data available.


Related in: MedlinePlus