Stromule branch tip detection based on accurate cell image segmentation

Stromule extension along microtubules coordinated with actin-mediated anchoring guides perinuclear chloroplast movement during innate immunity

“…Data represented as the mean standard error of the mean (SEM), ****p<0.0001 by a Student’s t-test with Welch’s correction. ( E ) A stromule tip was tracked using a combination of fuzzy c-means and active contour algorithm, with shape analysis to calculate the length of the stromule, the tip velocity and the association with microtubules ( Lu et al, 2017 ). Tip associations (green dots) with MTs (gray scale) were mapped over a time series.…”

“…The velocity of stromule extension was significantly lower when MTs were marked with EB1-Citrine (0.0565 µm/s) compared to GFP-TUA6 (0.146 µm/s) ( Figure 1D ). An automated algorithm for detecting stromule tips in maximum intensity projections was developed ( Lu et al, 2017 ). The MTs were segmented and skeletonized (data not shown).…”

“…Scale bar equal 10 µm. ( B ) Stromules and chloroplasts were tracked using the algorithm described in ( Lu et al, 2017 ). The chloroplasts on the left in panel A had two stromules (green) resulting in opposing forces and minimal movement of the chloroplast body (red).…”

“…These observations explain why the disruption of stromules by CTD was missed during 30-min treatment ( Figure 6—figure supplement 3 ). Tracking the stromule and chloroplast movement ( Lu et al, 2017 ) showed that stromules can still direct chloroplast movement if AFs are only partially disrupted. One chloroplast (Cp1) had restricted movement and colocalized with an AF fragment ( Figure 8—figure supplement 2A ).…”