scholarly journals Epidermal expression of a sterol biosynthesis gene regulates root growth by a non-cell-autonomous mechanism inArabidopsis

Development ◽  
2018 ◽  
Vol 145 (10) ◽  
pp. dev160572 ◽  
Author(s):  
Eleri Short ◽  
Margaret Leighton ◽  
Gul Imriz ◽  
Dongbin Liu ◽  
Naomi Cope-Selby ◽  
...  
2017 ◽  
Author(s):  
Eleri Short ◽  
Margaret Pullen ◽  
Gul Imriz ◽  
Dongbin Liu ◽  
Naomi Cope-Selby ◽  
...  

AbstractThe epidermis has been hypothesized to play a signalling role during plant development. One class of mutants showing defects in signal transduction and radial patterning are those in sterol biosynthesis. The expectation is that sterol biosynthesis is a constitutive cell-autonomous process for the maintenance of basic cellular functions. The HYDRA1 (HYD1) gene of Arabidopsis encodes an essential sterol Δ8-Δ7 isomerase, and although hyd1 mutant seedlings are defective in radial patterning of several tissues, we show that the HYD1 gene is expressed primarily in the root epidermis. Cell type-specific transgenic activation of HYD1 transcription reveals that HYD1 expression in the epidermis of hyd1 null mutants is sufficient to rescue root patterning and growth. Unexpectedly, expression of HYD1 in the vascular tissues and root meristem, though not endodermis or pericycle, also leads to phenotypic rescue. Phenotypic rescue is associated with rescued patterning of the PIN1 and PIN2 auxin efflux carriers. The importance of the epidermis is in part due to its role as a site for tissue-specific sterol biosynthesis, and auxin is a candidate for a non-cell autonomous signal.


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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