F‐actin and myosin XI play important roles in plant organelle movement. A few myosin XI genes in the genome of Arabidopsis are mainly expressed in mature pollen, which suggests that they may play a crucial role in pollen germination and pollen tube tip growth. In this study, a genetic complementation assay was conducted in a myosin xi‐c (myo11c1) myosin xi‐e (myo11c2) double mutant, and fluorescence labeling combined with microscopic observation was applied. We found that myosin XI‐E (Myo11C2)‐green fluorescent protein (GFP) restored the slow pollen tube growth and seed deficiency phenotypes of the myo11c1 myo11c2 double mutant and Myo11C2‐GFP partially colocalized with mitochondria, peroxisomes and Golgi stacks. Furthermore, decreased mitochondrial movement and subapical accumulation were detected in myo11c1 myo11c2 double mutant pollen tubes. Fluorescence recovery after photobleaching experiments showed that the fluorescence recoveries of GFP‐RabA4d and AtPRK1‐GFP at the pollen tube tip of the myo11c1 myo11c2 double mutant were lower than those of the wild type were after photobleaching. These results suggest that Myo11C2 may be associated with mitochondria, peroxisomes and Golgi stacks, and play a crucial role in organelle movement and apical accumulation of secretory vesicles in pollen tubes of Arabidopsis thaliana.

中文翻译：

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拟南芥花粉管中的细胞器运动和分泌小泡的顶端积累取决于XI类肌球蛋白

F-肌动蛋白和肌球蛋白XI在植物细胞器运动中起重要作用。拟南芥基因组中的一些肌球蛋白XI基因主要在成熟花粉中表达，这表明它们可能在花粉萌发和花粉管尖端生长中起关键作用。在这项研究中，在肌球蛋白xi-c（myo11c1）肌球蛋白xi-e（myo11c2）双突变体中进行了遗传互补测定，并应用了荧光标记和显微观察。我们发现肌球蛋白XI-E（Myo11C2）-绿色荧光蛋白（GFP）恢复了myo11c1 myo11c2的花粉管生长缓慢和种子缺乏表型双突变体和Myo11C2-GFP与线粒体，过氧化物酶体和高尔基体堆栈部分共定位。此外，在myo11c1 myo11c2双突变花粉管中检测到线粒体运动减少和根尖下积聚。光漂白实验后的荧光恢复结果表明，经过光漂白后，myo11c1 myo11c2双突变体的花粉管尖端的GFP‐RabA4d和AtPRK1‐GFP的荧光恢复率低于野生型。这些结果表明，Myo11C2可能与线粒体，过氧化物酶体和高尔基体堆积有关，并在拟南芥花粉管中的细胞器运动和分泌小泡的顶端积累中起关键作用。