Advertisement

Planta

, Volume 236, Issue 4, pp 999–1012 | Cite as

A possible involvement of autophagy in amyloplast degradation in columella cells during hydrotropic response of Arabidopsis roots

  • Mayumi Nakayama
  • Yasuko Kaneko
  • Yutaka Miyazawa
  • Nobuharu Fujii
  • Nahoko Higashitani
  • Shinya Wada
  • Hiroyuki Ishida
  • Kohki Yoshimoto
  • Ken Shirasu
  • Kenji Yamada
  • Mikio Nishimura
  • Hideyuki Takahashi
Original Article

Abstract

Seedling roots display not only gravitropism but also hydrotropism, and the two tropisms interfere with one another. In Arabidopsis (Arabidopsis thaliana) roots, amyloplasts in columella cells are rapidly degraded during the hydrotropic response. Degradation of amyloplasts involved in gravisensing enhances the hydrotropic response by reducing the gravitropic response. However, the mechanism by which amyloplasts are degraded in hydrotropically responding roots remains unknown. In this study, the mechanistic aspects of the degradation of amyloplasts in columella cells during hydrotropic response were investigated by analyzing organellar morphology, cell polarity and changes in gene expression. The results showed that hydrotropic stimulation or systemic water stress caused dramatic changes in organellar form and positioning in columella cells. Specifically, the columella cells of hydrotropically responding or water-stressed roots lost polarity in the distribution of the endoplasmic reticulum (ER), and showed accelerated vacuolization and nuclear movement. Analysis of ER-localized GFP showed that ER redistributed around the developed vacuoles. Cells often showed decomposing amyloplasts in autophagosome-like structures. Both hydrotropic stimulation and water stress upregulated the expression of AtATG18a, which is required for autophagosome formation. Furthermore, analysis with GFP-AtATG8a revealed that both hydrotropic stimulation and water stress induced the formation of autophagosomes in the columella cells. In addition, expression of plastid marker, pt-GFP, in the columella cells dramatically decreased in response to both hydrotropic stimulation and water stress, but its decrease was much less in the autophagy mutant atg5. These results suggest that hydrotropic stimulation confers water stress in the roots, which triggers an autophagic response responsible for the degradation of amyloplasts in columella cells of Arabidopsis roots.

Keywords

Autophagosome Endoplasmic reticulum (ER) Gravitropism Hydrotropism Water stress 

Abbreviations

ER

Endoplasmic reticulum

GFP

Green fluorescent protein

DAPI

4′,6-diamidino-2-phenylindole

DIC

Differential interference contrast microscope

TEM

Transmission electron microscope

RT-PCR

Reverse transcription-polymerase chain reaction

Notes

Acknowledgments

We thank Dr. Maureen R. Hanson of Cornell University for providing us with the seeds of pt-GFP transgenic plants. We are grateful to Dr. Atsushi Higashitani of the Graduate School of Life Sciences, Tohoku University for his helpful suggestions and critical reading of this manuscript. This work was supported by a Grant-in-Aid for Scientific Research B (No. 20370017) from the Japan Society for the Promotion of Science (JSPS) and a Grant-in-Aid for Scientific Research on Innovative Areas (No. 22120004) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) to H.T., a Research Fellowship for Young Scientists from the JSPS to M.N., and the Funding Program for Next-Generation World-Leading Researchers (GS002) to Y.M. This work was also carried out as a part of the Global COE Program J03 (Ecosystem Management Adapting to Global Change).

References

  1. Busch MB, Sievers A (1990) Hormone treatment of roots causes not only a reversible loss of starch but also of structural polarity in statocytes. Planta 181:358–364PubMedCrossRefGoogle Scholar
  2. Contento AL, Xiong Y, Bassham DC (2005) Visualization of autophagy in Arabidopsis using the fluorescent dye monodansylcadaverine and a GFP-AtATG8e fusion protein. Plant J 42:598–608PubMedCrossRefGoogle Scholar
  3. Correll MJ, Kiss JZ (2002) Interactions between gravitropism and phototropism in plants. J Plant Growth Regul 21:89–101PubMedCrossRefGoogle Scholar
  4. Darwin C, Darwin F (1880) The power of movement in plants. John Murray, LondonGoogle Scholar
  5. Eapen D, Barroso ML, Campos ME, Ponce G, Corkidi G, Dubrovsky JG, Cassab GI (2003) A no hydrotropic response root mutant that responds positively to gravitropism in Arabidopsis. Plant Physiol 131:536–546PubMedCrossRefGoogle Scholar
  6. Eapen D, Barroso ML, Ponce G, Campos ME, Cassab GI (2005) Hydrotropism: root growth responses to water. Trend Plant Sci 10:44–50CrossRefGoogle Scholar
  7. Hirasawa T, Takahashi H, Suge H, Ishihara K (1997) Water potential, turgor and cell wall properties in elongating tissues of the hydrotropically bending roots. Plant Cell Environ 20:381–386CrossRefGoogle Scholar
  8. Ishida H, Yoshimoto K, Izumi M, Reisen D, Yano Y, Makino A, Ohsumi Y, Hanson MR, Mae T (2008) Mobilization of rubisco and stroma-localized fluorescent proteins of chloroplasts to the vacuole by an ATG gene-dependent autophagic process. Plant Physiol 148:142–155PubMedCrossRefGoogle Scholar
  9. Iversen TH (1969) Elimination of geotropic responsiveness in roots of cress (Lepidium sativum) by removal of statolith starch. Physiol Plant 22:1251–1262PubMedCrossRefGoogle Scholar
  10. Jaffe MJ, Takahashi H, Biro RL (1985) A pea mutant for the study of hydrotropism in roots. Science 230:445–447PubMedCrossRefGoogle Scholar
  11. Kaneyasu T, Kobayashi A, Nakayama M, Fujii N, Takahashi H, Miyazawa Y (2007) Auxin response, but not its polar transport, plays a role in hydrotropism of Arabidopsis roots. J Exp Bot 58:1143–1150PubMedCrossRefGoogle Scholar
  12. Kiss JZ (2000) Mechanisms of the early phases of plant gravitropism. CRC Crit Rev Plant Sci 19:556–573CrossRefGoogle Scholar
  13. Kobayashi A, Takahashi A, Kakimoto Y, Miyazawa Y, Fujii N, Higashitani A, Takahashi H (2007) A gene essential for hydrotropism in roots. Proc Natl Acad Sci USA 104:4724–4729PubMedCrossRefGoogle Scholar
  14. Mitsuhashi N, Shimada T, Mano S, Nishimura M, Hara-Nishimura I (2000) Characterization of organelles in the vacuolar-sorting pathway by visualization with GFP in tobacco BY-2 cells. Plant Cell Physiol 41:993–1001PubMedCrossRefGoogle Scholar
  15. Miyazawa Y, Sakashita T, Funayama T, Hamada N, Negishi H, Kobayashi A, Kaneyasu T, Ooba A, Morohashi K, Kakizaki T, Wada S, Kobayashi Y, Fujii N, Takahashi H (2008) Effects of locally targeted heavy-ion and laser microbeam on root hydrotropism in Arabidopsis thaliana. J Radiat Res 49:373–379PubMedCrossRefGoogle Scholar
  16. Miyazawa Y, Takahashi A, Kobayashi A, Kaneyasu T, Fujii N, Takahashi H (2009) GNOM-mediated vesicular trafficking plays an essential role in hydrotropism of Arabidopsis roots. Plant Physiol 149:835–840PubMedCrossRefGoogle Scholar
  17. Monshausen GB, Sarah JS, Gilroy S (2008) Touch sensing and thigmotropism. In: Gilroy S, Masson PH (eds) Plant tropisms, Blackwell Publishing, Oxford, pp 91–122Google Scholar
  18. Muday GK (2001) Auxins and tropisms. J Plant Growth Regul 20:226–243PubMedCrossRefGoogle Scholar
  19. Nakagawa T, Kurose T, Hino T, Tanaka K, Kawamukai M, Niwa Y, Toyooka K, Matsuoka K, Jinbo T, Kimura T (2007) Development of series of gateway binary vectors, pGWBs, for realizing efficient construction of fusion genes for plant transformation. J Biosci Bioeng 104:34–41PubMedCrossRefGoogle Scholar
  20. Ruppel NJ, Hangarter RP, Kiss JZ (2001) Red-light-induced positive phototropism in Arabidopsis roots. Planta 212:424–430PubMedCrossRefGoogle Scholar
  21. Takahashi H (1997) Hydrotropism: the current state of our knowledge. J Plant Res 110:163–169PubMedCrossRefGoogle Scholar
  22. Takahashi H, Scott TK (1993) Intensity of hydrotropism for the induction of root hydrotropism and sensing of the hydrostimulus by the root cap. Plant Cell Environ 16:99–103PubMedCrossRefGoogle Scholar
  23. Takahashi H, Suge H (1991) Root hydrotropism of an agravitropic pea mutant, ageotropum. Physiol Plant 82:24–31CrossRefGoogle Scholar
  24. Takahashi N, Okada K, Goto N, Takahashi H (2002) Hydrotropism in abscisic acid, wavy, and gravitropic mutants of Arabidopsis thaliana. Planta 216:203–211PubMedCrossRefGoogle Scholar
  25. Takahashi N, Yamazaki Y, Kobayashi A, Higashitani A, Takahashi H (2003) Hydrotropism interacts with gravitropism by degrading amyloplasts in seedling roots of Arabidopsis and radish. Plant Physiol 132:805–810PubMedCrossRefGoogle Scholar
  26. Takahashi H, Miyazawa Y, Fujii N (2009) Hormonal interactions during root tropic growth: hydrotropism versus gravitropism. Plant Mol Biol 69:489–502PubMedCrossRefGoogle Scholar
  27. Thompson AR, Doelling JH, Suttangkakul A, Vierstra RD (2005) Autophagic nutrient recycling in Arabidopsis directed by the ATG8 and ATG12 conjugation pathways. Plant Physiol 138:2097–2110PubMedCrossRefGoogle Scholar
  28. Tooze SA, Yoshimori T (2010) The origin of the autophagosomal membrane. Nat Cell Biol 12:831–835PubMedCrossRefGoogle Scholar
  29. Wada S, Ishida H, Izumi M, Yoshimoto K, Ohsumi Y, Mae T, Makino A (2009) Autophagy plays a role in chloroplast degradation during senescence in individually darkened leaves. Plant Physiol 149:885–893PubMedCrossRefGoogle Scholar
  30. Wendt M, Sievers A (1989) The polarity of statocytes and gravisensitivity of roots are dependent on the concentration of calcium in statocytes. Plant Cell Physiol 30:929–932PubMedGoogle Scholar
  31. Xiong Y, Contento AL, Bassham DC (2005) AtATG18a is required for the formation of autophagosomes during nutrient stress and senescence in Arabidopsis thaliana. Plant J 2:535–546CrossRefGoogle Scholar
  32. Yoshimoto K, Hanaoka H, Sato S, Kato T, Tabata S, Noda T, Ohsumi Y (2004) Processing of ATG8s, ubiquitin-like proteins, and their deconjugation by ATG4s are essential for plant autophagy. Plant Cell 16:2967–2983PubMedCrossRefGoogle Scholar
  33. Zheng HQ, Staehelin LA (2001) Nodal endoplasmic reticulum, a specialized form of endoplasmic reticulum found in gravity-sensing root tip columella cells. Plant Physiol 125:252–265PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Mayumi Nakayama
    • 1
  • Yasuko Kaneko
    • 2
  • Yutaka Miyazawa
    • 1
  • Nobuharu Fujii
    • 1
  • Nahoko Higashitani
    • 1
  • Shinya Wada
    • 3
  • Hiroyuki Ishida
    • 3
  • Kohki Yoshimoto
    • 4
  • Ken Shirasu
    • 4
  • Kenji Yamada
    • 5
  • Mikio Nishimura
    • 5
  • Hideyuki Takahashi
    • 1
  1. 1.Graduate School of Life SciencesTohoku UniversitySendaiJapan
  2. 2.Faculty of EducationSaitama UniversitySaitamaJapan
  3. 3.Graduate School of AgricultureTohoku UniversitySendaiJapan
  4. 4.Plant Science Center, RIKENYokohamaJapan
  5. 5.National Institute for Basic BiologyOkazakiJapan

Personalised recommendations