Biology subjects

Tsukaya, H.

Publications and source records attributed to Tsukaya, H..

4 recordsLinked to original sources

bioRxiv2021

Bryophyte spermiogenesis occurs through multimode autophagic and nonautophagic degradation

Mitochondria change their morphology in response to developmental and environmental cues. During sexual reproduction, bryophytes produce spermatozoids with two mitochondria in the cell body. Although intensive morphological analyses have been conducted thus far, how this fixed number of mitochondria is realized remains unknown. Here, we investigated how mitochondria are reorganized during spermiogenesis in Marchantia polymorpha. We found that the mitochondrial number is reduced to one through fission followed by autophagic degradation during early spermiogenesis, and then the posterior mitochondrion arises by fission of the anterior mitochondrion. Autophagy is also responsible for the removal of other organelles, including peroxisomes, but these other organelles are removed at distinct developmental stages from mitochondrial degradation. We also found that spermiogenesis involves nonautophagic organelle degradation. Our findings highlight the dynamic reorganization of mitochondria, which is regulated distinctly from that of other organelles, and multiple degradation mechanisms operate in organelle remodeling during spermiogenesis in M. polymorpha.

plant biology↗

bioRxiv2021

Importance of cell division angle, position of cell proliferative area, and localization of AN3 in lateral organ morphology

Leaf meristem is a cell proliferative zone present in the lateral organ primordia. In this study, we investigated how the proliferative zone affects the final morphology of the lateral organs. We examined how cell proliferative zones differ in the primordia of planar floral organs and polar auxin transport inhibitor (PATI)-treated leaves from normal foliage leaf primordia of Arabidopsis thaliana with a focus on the spatial accumulation pattern of ANGUSTIFOLIA3 (AN3), a key element for leaf meristem positioning. We found that organ shape changes by PATI treatment were correlated to the angle of the cell division plane relative to the leaf primordia axis in the leaf meristem (cell division angle), but not with leaf-meristem positioning, size of the leaf meristem, or the localization pattern of AN3 protein. In contrast, different shapes between sepals and petals compared with foliage leaves were associated with both altered meristem position associated with altered AN3 expression patterns and different distributions of cell division angles. These results suggest that lateral organ shapes are regulated via two aspects: position of meristem and cell division angles Summary statementDifferent lateral organs with different morphology possess different properties of meristems; cell division angles, position of cell proliferative area and AN3 localization patterns.

plant biology↗

bioRxiv2021

A simple Agrobacterium-mediated stable transformation technique for the hornwort model Anthoceros agrestis

We have developed a simple Agrobacterium-mediated method for the stable transformation of the hornwort Anthoceros agrestis, the fifth bryophyte species for which a genetic manipulation technique becomes available. High transformation efficiency was achieved by using thallus tissue grown under low-light conditions. We generated a total of 216 transgenic A. agrestis lines expressing the {beta}-Glucuronidase (GUS), cyan, green, and yellow fluorescent proteins under the control of the CaMV 35S promoter and several endogenous promoters. Nuclear and plasma membrane localization with multiple color fluorescent proteins was also confirmed. The transformation technique described here should pave the way for detailed molecular and genetic studies of hornwort biology, providing much needed insight into the molecular mechanisms underlying symbiosis, carbon-concentrating mechanism, RNA editing, and land plant evolution in general.

plant biology↗

bioRxiv2020

The molecular framework of heterophylly in Callitriche palustris L. differs from that in other amphibious plants

Heterophylly refers to the development of different leaf forms in a single plant depending on the environmental conditions. It is often observed in amphibious aquatic plants that can grow under aerial and submerged conditions. Although heterophylly is well recognized in aquatic plants, the associated developmental mechanisms and the molecular basis remain unclear. In this study, we analyzed heterophyllous leaf formation in an aquatic plant, Callitriche palustris, to clarify the underlying developmental and molecular mechanisms. Morphological analyses revealed extensive cell elongation and the rearrangement of cortical microtubules in the elongated submerged leaves of C. palustris. Our observations also suggested that gibberellin, ethylene, and abscisic acid regulate the formation of submerged leaves. However, the perturbation of one or more of the hormones was insufficient to induce the formation of submerged leaves under aerial conditions. Finally, we analyzed gene expression changes during aerial and submerged leaf development and narrowed down the candidate genes controlling heterophylly via transcriptomic comparisons, including a comparison with a closely related terrestrial species. We revealed that the molecular mechanism regulating heterophylly in C. palustris is associated with hormonal changes and diverse transcription factor gene expression profiles, suggesting differences from the corresponding mechanisms in previously investigated amphibious plants.

plant biology↗