Plants modify biological processes to ensure survival following carbon depletion: a Lolium perenne model.
BACKGROUND
Plants, due to their immobility, have evolved mechanisms allowing them to adapt to multiple environmental and management conditions. Short-term undesirable conditions (e.g. moisture deficit, cold temperatures) generally reduce photosynthetic carbon supply while increasing soluble carbohydrate accumulation. It is not known, however, what strategies plants may use in the long-term to adapt to situations resulting in net carbon depletion (i.e. reduced photosynthetic carbon supply and carbohydrate accumulation). In addition, many transcriptomic experiments have typically been undertaken under laboratory conditions; therefore, long-term acclimation strategies that plants use in natural environments are not well understood.


RESULTS
Perennial ryegrass (Lolium perenne L.) was used as a model plant to define whether plants adapt to repetitive carbon depletion and to further elucidate their long-term acclimation mechanisms. Transcriptome changes in both lamina and stubble tissues of field-grown plants with depleted carbon reserves were characterised using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The RT-qPCR data for select key genes indicated that plants reduced fructan degradation, and increased photosynthesis and fructan synthesis capacities following carbon depletion. This acclimatory response was not sufficient to prevent a reduction (P<0.001) in net biomass accumulation, but ensured that the plant survived.


CONCLUSIONS
Adaptations of plants with depleted carbon reserves resulted in reduced post-defoliation carbon mobilization and earlier replenishment of carbon reserves, thereby ensuring survival and continued growth. These findings will help pave the way to improve plant biomass production, for either grazing livestock or biofuel purposes.
Lee
Julia M
JM
DairyNZ Ltd, Hamilton, New Zealand. julia.lee@dairynz.co.nz
Sathish
Puthigae
P
Donaghy
Daniel J
DJ
Roche
John R
JR
D001692:Biological Transport / Q000235:genetics; D018533:Biomass; D050260:Carbohydrate Metabolism / Q000235:genetics; D002244:Carbon / Q000172:deficiency* / Q000378:metabolism; D005630:Fructans / Q000096:biosynthesis / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008129:Lolium / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008954:Models, Biological; D010788:Photosynthesis / Q000235:genetics; D012995:Solubility; D014867:Water / Q000737:chemistry
D005630:Fructans; D014867:Water; D002244:Carbon
Plant Cell Environ. 2007 Sep;30(9):1126-49
17661751
Science. 2006 Jun 30;312(5782):1918-21
16809532
Plant Cell. 2005 Dec;17(12):3257-81
16299223
Planta. 2006 Oct;224(5):1080-90
16685524
BMC Mol Biol. 2010 Jan 20;11:8
20089196
J Plant Physiol. 2003 Nov;160(11):1385-91
14658392
Planta. 2001 May;213(1):109-20
11523646
Nat Rev Genet. 2008 Aug;9(8):583-93
18591982
Plant Physiol. 2009 Jan;149(1):71-81
19126697
Cancer Res. 2004 Aug 1;64(15):5245-50
15289330
Curr Opin Plant Biol. 2007 Jun;10(3):227-35
17434793
Methods Mol Biol. 2000;132:365-86
10547847
Funct Plant Biol. 2007 Jun;34(5):418-430
32689369
Plant Mol Biol. 2008 Jun;67(3):197-214
18299801
Plant Physiol. 2003 Nov;133(3):1190-7
14563929
Plant Physiol. 2004 Jun;135(2):622-9
15208410
New Phytol. 2008;178(4):766-780
18346102
Plant Biotechnol J. 2005 Sep;3(5):459-74
17173633
J Exp Bot. 2003 Apr;54(385):1231-43
12654874
Plant J. 1997 Sep;12(3):605-14
9351245
Plant Biotechnol J. 2007 Jan;5(1):146-61
17207264
Plant Cell Physiol. 2009 Jul;50(7):1329-44
19520670
J Exp Bot. 2003 Jan;54(382):539-47
12508065