Down-regulation of hydroxycinnamoyl CoA: Shikimate hydroxycinnamoyl transferase in transgenic alfalfa affects lignification, development and forage quality

Shadle, Gail; Chen, Fang; Reddy, M. Sreenath; Jackson, Lisa A.; Nakashima, Jin; Dixon, Richard A.

doi:10.1016/j.phytochem.2007.03.022

Cited by 227 publications

(216 citation statements)

References 28 publications

Supporting

Mentioning

195

Contrasting

Unclassified

Order By: Relevance

“…This apparent reduction in lignin levels was confirmed by thioacidolysis, which revealed decreased levels of both guaiacyl and syringyl lignin monomer units, with an increase in the p-hydroxyphenyl monomer units (Fig. 2B) in the roots, characteristic of the lignin composition previously reported in stems of HCT downregulated plants (Shadle et al, 2007) and also found here ( Fig. 2A).…”

Section: Root Characteristics Of Reduced-lignin Alfalfasupporting

confidence: 88%

“…Previous studies have shown that HCT down-regulated alfalfa plants exhibit a dwarf phenotype (Shadle et al, 2007;Gallego-Giraldo et al, 2011a, 2011b; however, these studies did not evaluate the effects of lignin downregulation on root growth and development. Therefore, we performed a phenotypic characterization of roots from HCT down-regulated alfalfa lines on plants with a confirmed reduction of HCT transcript levels in roots assessed by quantitative real-time (qRT)-PCR (Supplemental Fig.…”

Section: Root Characteristics Of Reduced-lignin Alfalfamentioning

confidence: 98%

“…For example, some transgenic reducedlignin tobacco (Nicotiana tabacum) lines show biomass reduction, while in other cases, there is no visible phenotype (Chabannes et al, 2001). Transgenic alfalfa (Medicago sativa) lines down-regulated in hydroxycinnamoyl coenzyme A:shikimate hydroxycinnamoyl transferase (HCT) exhibit the greatest improvements in saccharification efficiency, as well as the greatest reduction in yield, among a series of lines independently down-regulated at different steps in the monolignol pathways Shadle et al, 2007). Growth inhibition of HCT down-regulated alfalfa plants is associated with hormonal imbalances, altered GA perception, and a massive induction of defense gene transcripts (Gallego-Giraldo et al, 2011b).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Lignin Modification Leads to Increased Nodule Numbers in Alfalfa

et al. 2014

Self Cite

View full text Add to dashboard Cite

Reduction of lignin levels in the forage legume alfalfa (Medicago sativa) by down-regulation of the monolignol biosynthetic enzyme hydroxycinnamoyl coenzyme A:shikimate hydroxycinnamoyl transferase (HCT) results in strongly increased digestibility and processing ability of lignocellulose. However, these modifications are often also associated with dwarfing and other changes in plant growth. Given the importance of nitrogen fixation for legume growth, we evaluated the impact of constitutively targeted lignin modification on the belowground organs (roots and nodules) of alfalfa plants. HCT downregulated alfalfa plants exhibit a striking reduction in root growth accompanied by an unexpected increase in nodule numbers when grown in the greenhouse or in the field. This phenotype is associated with increased levels of gibberellins and certain flavonoid compounds in roots. Although HCT down-regulation reduced biomass yields in both the greenhouse and field experiments, the impact on the allocation of nitrogen to shoots or roots was minimal. It is unlikely, therefore, that the altered growth phenotype of reduced-lignin alfalfa is a direct result of changes in nodulation or nitrogen fixation efficiency. Furthermore, HCT down-regulation has no measurable effect on carbon allocation to roots in either greenhouse or 3-year field trials.

show abstract

Section: Root Characteristics Of Reduced-lignin Alfalfasupporting

confidence: 88%

Section: Root Characteristics Of Reduced-lignin Alfalfamentioning

confidence: 98%

mentioning

confidence: 99%

See 1 more Smart Citation

Lignin Modification Leads to Increased Nodule Numbers in Alfalfa

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…H-lignin (or H-unit) arises from p-coumaryl alcohol, G-lignin from coniferyl alcohol, and S-lignin from sinapyl alcohol (Boerjan et al 2003). However, plants have the capacity to incorporate a range of molecules such as 5-hydroxyconiferyl alcohol and diVerent cinnamylaldehydes into the lignocellulosic matrix (Humphreys et al 1999;Anterola and Lewis 2002;Boerjan et al 2003;Barrière et al 2004;Shadle et al 2007;Rastogi and Dwivedi 2008). Grasses also contain signiWcant amounts of p-coumaric acid (pCA) and ferulic acid (FA), predominantly crosslinked to cell wall lignin and polysaccharide through ester and ether linkages (Grabber et al 1991;Dixon et al 2001;Chen et al 2002;Boerjan et al 2003;Grabber and Lu 2007).…”

Section: Introductionmentioning

confidence: 99%

Genetic background impacts soluble and cell wall-bound aromatics in brown midrib mutants of sorghum

Palmer

Sattler

Saathoff

et al. 2008

Planta

149

View full text Add to dashboard Cite

“…Increasing cell wall carbohydrate (principally as cellulose) content in biomass can be expected to increase liquid fuel yield. Decreasing lignin content is also expected to enhance cellulose breakdown, and has been a major target for conventional and molecular breeding [17,18,[87][88][89]104]. However, lowering lignin content could have a negative impact on plant Wtness and survivability of perennial species under Weld conditions [12,70].…”

Section: Introductionmentioning

confidence: 99%

Opportunities and roadblocks in utilizing forages and small grains for liquid fuels

Sarath

Mitchell

Sattler

et al. 2008

J Ind Microbiol Biotechnol

134

View full text Add to dashboard Cite

Sarath, Gautam; Mitchell, Robert B.; Sattler, S. E.; Funnell, Deanna L.; Pedersen, Jeffrey F.; Graybosch, Robert A.; and Vogel, Kenneth P., "Opportunities and roadblocks in utilizing forages and small grains for liquid fuels" (2008 Abstract This review focuses on the potential advantages and disadvantages of forages such as switchgrass (Panicum virgatum), and two small grains: sorghum (Sorghum bicolor), and wheat (Triticum aesitvum), as feedstocks for biofuels. It highlights the synergy provided by applying what is known from forage digestibility and wheat and sorghum starch properties studies to the biofuels sector. Opportunities therefore, exist to improve biofuel qualities in these crops via genetics and agronomics. In contrast to cereal crops, switchgrass still retains tremendous exploitable genetic diversity, and can be speciWcally improved to Wt a particular agronomic, management, and conversion platform. Combined with emerging studies on switchgrass genomics, conversion properties and management, the future for genetic modiWcation of this species through conventional and molecular breeding strategies appear to be bright. The presence of brown-midrib mutations in sorghum that alter cell wall composition by reducing lignin and other attributes indicate that sorghum could serve as an important model species for C 4 -grasses. Utilization of the brown-midrib traits could lead to the development of forage and sweet sorghums as novel biomass crops. Additionally, wheat crop residue, and wheat and sorghum with improved starch content and composition represent alternate biofuel sources. However, the use of wheat starch as a biofuel is unlikely but its value as a model to study starch properties on biofuel yields holds signiWcant promise.

show abstract

Down-regulation of hydroxycinnamoyl CoA: Shikimate hydroxycinnamoyl transferase in transgenic alfalfa affects lignification, development and forage quality

Cited by 227 publications

References 28 publications

Lignin Modification Leads to Increased Nodule Numbers in Alfalfa

Lignin Modification Leads to Increased Nodule Numbers in Alfalfa

Genetic background impacts soluble and cell wall-bound aromatics in brown midrib mutants of sorghum

Opportunities and roadblocks in utilizing forages and small grains for liquid fuels

Contact Info

Product

Resources

About