Accelerated root growth induced by nitrate deficit is related to apoplast acidification

2010 ◽  
Vol 57 (4) ◽  
pp. 485-493 ◽  
Author(s):  
O. V. Skobeleva ◽  
I. N. Ktitorova ◽  
K. G. Agal’tsov
2021 ◽  
Author(s):  
Lanxin Li ◽  
Inge Verstraeten ◽  
Mark Roosjen ◽  
Koji Takahashi ◽  
Lesia Rodriguez ◽  
...  

Abstract Growth regulation tailors plant development to its environment. A showcase is growth adaptation to gravity, where shoots bend up and roots down. This paradox is based on different responses to the phytohormone auxin, which promotes cell expansion in shoots, while inhibiting it in roots via a yet unknown cellular mechanism. Here, by combining microfluidics, live imaging, genetic engineering and phospho-proteomics in Arabidopsis thaliana, we reveal how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on the rapid regulation of the apoplastic pH, which is the direct growth-determining mechanism. Cell surface-based TRANSMEMBRANE KINASE 1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular TIR1/AFB-mediated signalling triggers net cellular H+-influx, causing apoplast alkalinisation. The simultaneous activation of these two counteracting mechanisms poises the root for a rapid, fine-tuned growth modulation to subtle changes in the environment.


2021 ◽  
Author(s):  
Lanxin Li ◽  
Inge Verstraeten ◽  
Mark Roosjen ◽  
Koji Takahashi ◽  
Lesia Rodriguez ◽  
...  

Abstract Growth regulation tailors plant development to its environment. A showcase is response to gravity, where shoots bend up and roots down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots, while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phospho-proteomics in Arabidopsis thaliana, we advance our understanding how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on the rapid regulation of the apoplastic pH, a causative growth determinant. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+-influx, causing apoplast alkalinisation. The simultaneous activation of these two counteracting mechanisms poises the root for a rapid, fine-tuned growth modulation while navigating complex soil environment.


2021 ◽  
Author(s):  
Lanxin Li ◽  
Inge Verstraeten ◽  
Mark Roosjen ◽  
Koji Takahashi ◽  
Lesia Rodriguez ◽  
...  

Abstract Growth regulation tailors plant development to its environment. A showcase is response to gravity, where shoots bend up and roots down1. This paradox is based on opposite effects of the phytohormone auxin, which promotes cell expansion in shoots, while inhibiting it in roots via a yet unknown cellular mechanism2. Here, by combining microfluidics, live imaging, genetic engineering and phospho-proteomics in Arabidopsis thaliana, we advance our understanding how auxin inhibits root growth. We show that auxin activates two distinct, antagonistically acting signalling pathways that converge on the rapid regulation of the apoplastic pH, a causative growth determinant. Cell surface-based TRANSMEMBRANE KINASE1 (TMK1) interacts with and mediates phosphorylation and activation of plasma membrane H+-ATPases for apoplast acidification, while intracellular canonical auxin signalling promotes net cellular H+-influx, causing apoplast alkalinisation. The simultaneous activation of these two counteracting mechanisms poises the root for a rapid, fine-tuned growth modulation while navigating complex soil environment.


1994 ◽  
Vol 92 (4) ◽  
pp. 675-680 ◽  
Author(s):  
Iduna Arduini ◽  
Douglas L. Godbold ◽  
Antonino Onnis

Author(s):  
K.H. Widdup ◽  
T.L. Knight ◽  
C.J. Waters

Slow establishment of caucasian clover (Trifolium ambiguum L.) is hindering the use of this legume in pasture mixtures. Improved genetic material is one strategy of correcting the problem. Newly harvested seed of hexaploid caucasian clover germplasm covering a range of origins, together with white and red clover and lucerne, were sown in 1 m rows in a Wakanui soil at Lincoln in November 1995. After 21 days, the caucasian clover material as a group had similar numbers of emerged seedlings as white clover and lucerne, but was inferior to red clover. There was wide variation among caucasian clover lines (48-70% seedling emergence), with the cool-season selection from cv. Monaro ranked the highest. Recurrent selection at low temperatures could be used to select material with improved rates of seedling emergence. Red clover and lucerne seedlings produced significantly greater shoot and root dry weight than caucasian and white clover seedlings. Initially, caucasian clover seedlings partitioned 1:1 shoot to root dry weight compared with 3:1 for white clover. After 2 months, caucasian clover seedlings had similar shoot growth but 3 times the root growth of white clover. Between 2 and 5 months, caucasian clover partitioned more to root and rhizome growth, resulting in a 0.3:1 shoot:root ratio compared with 2:1 for white clover. Both clover species had similar total dry weight after 5 months. Unhindered root/ rhizome devel-opment is very important to hasten the establishment phase of caucasian clover. The caucasian clover lines KZ3 and cool-season, both selections from Monaro, developed seedlings with greater shoot and root growth than cv. Monaro. KZ3 continued to produce greater root growth after 5 months, indicating the genetic potential for improvement in seedling growth rate. Different pasture estab-lishment techniques are proposed that take account of the seedling growth characteristics of caucasian clover. Keywords: establishment, genetic variation, growth, seedling emergence, Trifolium ambiguum


2005 ◽  
Vol 33 (4) ◽  
pp. 697-704 ◽  
Author(s):  
Adriana Sánchez-Urdaneta ◽  
Cecilia Peña-Valdivia ◽  
Carlos Trejo ◽  
J. Aguirre R. ◽  
Elizabeth Cárdenas S.

2013 ◽  
Vol 12 (10) ◽  
pp. 695-701
Author(s):  
Herve Martial Poumale Poumale ◽  
Alphonsine Nkapwa Guedem ◽  
Louis Pergaud Sandjo ◽  
Bonaventure Tchaleu Ngadjui ◽  
Yoshihito Shiono

A new lupane type triterpene (1), together with betulinic acid (2), friedelin (3), aristolochic acid I (4), alpinumisoflavone (5) and 4’-O-methylepinumisoflavone (6) have been isolated from the leaves of Thecacoris annobonea. The structure of the new compound was elucidated on the basis of 1 and 2D NMR experiments. The isolated compounds were evaluated for their phytotoxicity and antimicrobial activity. 1 exhibited significant antimicrobial activity at 30 μg/ml and compounds 1, 2, 3, 4, 5 and 6 inhibited root growth lettuce at 100 μg/ml. 


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