Institute of Cellular and Molecular Botany (IZMB)

Department of Ecophysiology

Elongases involved in suberin bionsynthesis in roots

The role of elongases in the formation of suberin in roots of Arabidopsis

A functional genomics approach is under way in order to identify fatty acid elongase condensing enzymes involved in Arabidopsis root suberin biosynthesis.

 

Principle investigators: Lukas Schreiber and Rochus Franke

 

Summary

Apoplastic depositions of the polyester suberin form physiological important plant-environment interfaces in shoots and roots.  They act as barriers protecting from uncontrolled water loss, nutrient depletion and invasion by pathogens [reviewed in 1].  Furthermore, plants respond to environmental stimuli by modifying the degree of suberization in root cell walls.  Despite the physiological importance of suberin a great gap in our knowledge exists about genes involved in suberin biosynthesis and deposition.  This is primarily due to the lack of appropriate molecular genetic attributes of the investigated species.  As a basis for molecular genetic approaches we established the tissue distribution and chemical composition of root suberin from Arabidopsis [2].  Arabidopsis suberin is characterized by oxygenated and partially unsaturated very long chain fatty acid derivatives.  The chain-length distribution ranging from C16 to C24, indicates that fatty acid elongases (FAE) are essential for suberin biosynthesis.  The FAE1-like gene family of β-KETOACYL-CoA SYNTHASES (KCS) is investigated for their potential involvement in root suberin biosynthesis by determination of the spatial and responsive expression pattern and biochemical suberin phenotyping of insertion mutants.

 

 

Support

This work is supported by the Deutsche Forschungsgemeinschaft (D.F.G.).

 

References

1. Franke R, Schreiber L. (2007) Suberin – a biopolyester forming apoplastic plant interfaces. Current Opinion in Plant Biology 10: 252-259 (Abstract)
2. Franke R, Briesen I, Wojciechowski T, Faust A, Yephremov A, Nawrath C, Schreiber L (2005) Apoplastic polyesters in Arabidopsis surface tissues - A typical suberin and a particular cutin. Phytochemistry 66: 2643-2658 (Abstract)

 

The Arabidopsis Gene Family of β-KETOACYL-CoA SYNTHASES (KCS)

AGI code Name as published	Project Name	Root expression			Assumed function; Ref. / Products of catalytic function; Ref.
		cDNA’s from Root1 ROOT derived EST / ALL EST	MPSS Signals2 [rel. signature abundance] Root vs. tissue with highest signature abundance	Microarray3 Σ root expression signals tissue expression [% of root expression signal]
At1g01120 KCS1	FAE-KCS1	2/20	12 : 215 (slique)	2483 coretex & endodermis stage 3 (31%)	Wax biosynthesis Todd et al. 1999 Suberin biosynthesis own results / C20/C20:1, C22, C24, C26; Todd et al. 1999
At1g04220	FAE-KCS17	1/7	24 : 295 (slique)	128 endodermis stage 3 (27%)	Suberin biosynthesis own results / C22; C24; Trenkamp et al. 2004
At1g07720	FAE-KCS3	0/17	3 : 203 (slique)	135 no differential expression	Unknown
At1g19440	FAE-KCS4	4/9	53 : 42 (slique)	2074 coretex & endodermis stage 3 (12%)	Suberin biosynthesis Own results
At1g25450 CER60	FAE-KCS5	0/5	5 : 244 (inflorescence)	688 epidermis stage 2 (21%)	Wax biosynthesis Hooker et al. 2002 / C20:1, C26, C28, C30; Trenkamp et al. 2004
At1g68530 CER6/CUT1	FAE-KCS6	0/62	3 : 962 (inflorescence)	188 no differential expression	Wax biosynthesis Millar et al. 1999 /
At1g71160	FAE-KCS7	NO EST	0: 31 (inflorescence)	128 no differential expression	Unknown
At2g15090	FAE-KCS8	1/10	2 : 53 (inflorescence)	285 no differential expression	Unknown
At2g16280	FAE-KCS9	0/21	25 : 26 (inflorescence)	2675 no differential expression	Unknown
At2g26250 FDH	FAE-KCS10	0/78	24 : 868 (inflorescence)	252 epidermis stage 3 (31%)	Cuticle development, trichome formation Yephremov et al. 1999
At2g26640	FAE-KCS11	1/10	12 : 10 (inflorescence)	1173 epidermis stage 2 (15%)	Unknown
At2g28630	FAE-KCS12		0 : 292 (inflorescence)	83 no differential expression	Unknown
At2g46720 HIC	FAE-KCS13	One EST that also matches At3g10280	0 : 18 (inflorescence)	215 endo stage 3 (15%)	Cuticle/stomatal development Gray et al. 2000
At3g10280	FAE-KCS14	One EST that also matches At2g46720	0 : 18 (inflorescence)	Not on affychip	Unknown
At3g52160	FAE-KCS15	0/1	0 : 144 (inflorescence)	233 no differential expression	Unknown
At4g34250	FAE-KCS16	0/8	0 : 0	105 epidermis stage 1 (26%)	Unknown
At4g34510 KCS2	FAE-KCS2	0/3	0 : 22 (inflorescence)	55 rootcap (23%)	Wax biosynthesis Clemens&Kunst, 2001 / C20, C20:1, C24, C26, Clemens&Kunst, 2001
At4g34520 FAE1	FAE-KCS18	0/22	0 : 0	209 no differential expression	Seed lipid biosynthesis James et al. 1995 / C20, C20:1, C20:2, C22, C22:1 Millar et al. 1997
At5g04530	FAE-KCS21	1/9	0: 1 (leaf)	105 no differential expression	Unknown
At5g43760	FAE-KCS19	1/16	195 : 447 (inflorescence)	1442 coretex&endodermis stage 3 (22%)	Unknown C22, C24 Trenkamp et al. 2004
At5g49070	FAE-KCS20	NO EST	0 : 11 (inflorescence)	193 no differential expression	Unknown

 

Foot notes:      1 NCBI 2004

                            2 Arabidopsis MPSS

                            3 Birnbaum et al. 2003