Convergent Evolution of Syringyl Lignin Biosynthesis via Distinct Pathways in the Lycophyte Selaginella and Flowering Plants

Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA.
The Plant Cell (Impact Factor: 9.34). 04/2010; 22(4):1033-45. DOI: 10.1105/tpc.109.073528
Source: PubMed


Phenotypic convergence in unrelated lineages arises when different organisms adapt similarly under comparable selective pressures. In an apparent example of this process, syringyl lignin, a fundamental building block of plant cell walls, occurs in two major plant lineages, lycophytes and angiosperms, which diverged from one another more than 400 million years ago. Here, we show that this convergence resulted from independent recruitment of lignin biosynthetic cytochrome P450-dependent monooxygenases that route cell wall monomers through related but distinct pathways in the two lineages. In contrast with angiosperms, in which syringyl lignin biosynthesis requires two phenylpropanoid meta-hydroxylases C3'H and F5H, the lycophyte Selaginella employs one phenylpropanoid dual meta-hydroxylase to bypass several steps of the canonical lignin biosynthetic pathway. Transgenic expression of the Selaginella hydroxylase in Arabidopsis thaliana dramatically reroutes its endogenous lignin biosynthetic pathway, yielding a novel lignin composition not previously identified in nature. Our findings demonstrate a unique case of convergent evolution via distinct biochemical strategies and suggest a new way to genetically reconstruct lignin biosynthesis in higher plants.

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    • "Ліг нін є ком плек сом мо но ліг ні нів, які утво рюють ся із р-гід ро кси фе ні ло вих, гвая ци ло вих і сирин гі ло вих скла до вих (Adler, 1977), що за лу ча ються до по лі ме ри за ції ліг ні ну та різ нять ся за сту пенем ме ток си лю ван ня (Leisola et al., 2012). Ві до мо, що мо но ліг нін вхо дить до ліг ні ну су дин них рос лин (Weng et al., 2010). Пи тан ня щодо вмісту мо но ліг нінів , їхньо го спів від но шен ня та ролі ок ре мих із них у лист ках гід ро фі тів у про це сі при род ної адап та ції рос лин до вод но го ото чен ня ли ша єть ся від кри тим. "

    Full-text · Article · Aug 2015
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    • "Тоб то пос тій не вод не ото чен ня є од ним з основ них ек зо ген них фак то рів під ви ще но го син те зу си рин гі лу та гвая ци лу в лист ках до слі джу ва них гідро фі тів. Ок рім того, оче вид но, на яв ність си рин гі лу та гвая ци лу, їх від но шен ня в клі тин них обо лон ках епі дер мі су, ме зо фі лу та су ди нах про від них пуч ків ко ре лює з да ни ми, от ри ма ни ми сто сов но представни ків дво доль них по кри то на сін них (Baucher et al., 1998; Weng et al., 2010). "
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    ABSTRACT: The comparative cytochemical analysis of the localization of monolignins (syringyl and quaiacyl) in epidermis, photosynthesizing parenchyma and vessels cell walls of submerged leaves of Myriophyllum spicatum, Potamogeton pectinatus and P. perfoliatus was carried using laser confocal microscopy. The images of quantitative distribution of monolignins in cell walls were obtained depending on the type of leaf tissue and plant species.
    Full-text · Article · Jan 2015
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    • " the highest being 88% in the ccr mutant ( Van Acker et al . , 2013 ) . The hydrolysis of Arabidopsis mutants shows that increases of cellulose saccharification by engineering monolignol biosynthesis can be the basis for monolignol pathway engineering in other species . Different species may have alternative routes for mono - lignol biosynthesis ( Weng et al . , 2010 ; Zhou et al . , 2010 ) , and down - regulation of specific monolignol pathway genes in different species may not have the same effects . For example , down - regulation of C3H in Arabidopsis caused reduction of both G and S monolignols ( Ralph et al . , 2006 ) . However , in a hybrid poplar ( Populus alba 9 grandidentata ) , the lignin"
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    ABSTRACT: Lignocelluloses from plant cell walls are attractive resources for sustainable biofuel production. However, conversion of lignocellulose to biofuel is more expensive than other current technologies, due to the costs of chemical pretreatment and enzyme hydrolysis for cell wall deconstruction. Recalcitrance of cell walls to deconstruction has been reduced in many plant species by modifying plant cell walls through biotechnology. These results have been achieved by reducing lignin content and altering its composition and structure. Reduction of recalcitrance has also been achieved by manipulating hemicellulose biosynthesis and by overexpression of bacterial enzymes in plants to disrupt linkages in the lignin-carbohydrate complexes. These modified plants often have improved saccharification yield and higher ethanol production. Cell wall-degrading (CWD) enzymes from bacteria and fungi have been expressed at high levels in plants to increase the efficiency of saccharification compared with exogenous addition of cellulolytic enzymes. In planta expression of heat-stable CWD enzymes from bacterial thermophiles has made autohydrolysis possible. Transgenic plants can be engineered to reduce recalcitrance without any yield penalty, indicating that successful cell wall modification can be achieved without impacting cell wall integrity or plant development. A more complete understanding of cell wall formation and structure should greatly improve lignocellulosic feedstocks and reduce the cost of biofuel production.
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