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Effects of PHENYLALANINE AMMONIA LYASE (PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium.

Cass CL, Peraldi A, Dowd PF, Mottiar Y, Santoro N, Karlen SD, Bukhman YV, Foster CE, Thrower N, Bruno LC, Moskvin OV, Johnson ET, Willhoit ME, Phutane M, Ralph J, Mansfield SD, Nicholson P, Sedbrook JC - J. Exp. Bot. (2015)

Bottom Line: The cell walls of stems of BdPAL-knockdown plants had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion.RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions.The data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA.

No MeSH data available.


Related in: MedlinePlus

Growth of BdPAL RNAi1-1 and 1-3 plants compared with the WT or empty vector control (CTL). (A) Time course measurements of the longest leaf lengths and tallest culm heights of BdPAL RNAi1-1 plants. Arrows delineate the time points at which 50% of the spikelets could be seen emerging from the leaf whorl. (B) Average daily root growth of BdPAL RNAi1-1 and WT seedlings. n=48. (C, D) Average above-ground senesced biomass dry weight (C) and final culm heights (D). Columns grouped together represent plants grown concurrently. Bars denote the SD. Asterisks represent Student’s t-test significant differences (P<0.03). 5<n<25.
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Figure 4: Growth of BdPAL RNAi1-1 and 1-3 plants compared with the WT or empty vector control (CTL). (A) Time course measurements of the longest leaf lengths and tallest culm heights of BdPAL RNAi1-1 plants. Arrows delineate the time points at which 50% of the spikelets could be seen emerging from the leaf whorl. (B) Average daily root growth of BdPAL RNAi1-1 and WT seedlings. n=48. (C, D) Average above-ground senesced biomass dry weight (C) and final culm heights (D). Columns grouped together represent plants grown concurrently. Bars denote the SD. Asterisks represent Student’s t-test significant differences (P<0.03). 5<n<25.

Mentions: To determine if BdPAL RNAi1-1 and 1-3 plants were affected in growth and development, lengths of leaves and culm heights were measured over time, revealing a slight but significant delay in growth of plants from both lines compared with the CTL (Fig. 4A; Supplementary Fig. S5A at JXB online). The culms of RNAi1-1 and 1-3 plants typically emerged and flowered a few days later than did CTL culms, suggestive of developmental delays. Moreover, RNAi1-1 and 1-3 culms grew to heights that, on average, were slightly shorter than the WT or CTL. RNAi knocked-down plants also accumulated slightly less above-ground biomass. Although the differences were not always statistically significant (Fig. 4B, C), they were significant in some experimental replicates, suggesting that the degree of PAL knockdown in these plants may be near the threshold of causing a yield penalty under controlled growth chamber conditions. More significantly, root growth assays revealed that BdPAL RNAi1-1 roots grew, on average, 60% more slowly than WT roots (Fig. 4B). While the underlying cause of the reduced root growth remains unclear, less extensive root systems could adversely impact above-ground growth.


Effects of PHENYLALANINE AMMONIA LYASE (PAL) knockdown on cell wall composition, biomass digestibility, and biotic and abiotic stress responses in Brachypodium.

Cass CL, Peraldi A, Dowd PF, Mottiar Y, Santoro N, Karlen SD, Bukhman YV, Foster CE, Thrower N, Bruno LC, Moskvin OV, Johnson ET, Willhoit ME, Phutane M, Ralph J, Mansfield SD, Nicholson P, Sedbrook JC - J. Exp. Bot. (2015)

Growth of BdPAL RNAi1-1 and 1-3 plants compared with the WT or empty vector control (CTL). (A) Time course measurements of the longest leaf lengths and tallest culm heights of BdPAL RNAi1-1 plants. Arrows delineate the time points at which 50% of the spikelets could be seen emerging from the leaf whorl. (B) Average daily root growth of BdPAL RNAi1-1 and WT seedlings. n=48. (C, D) Average above-ground senesced biomass dry weight (C) and final culm heights (D). Columns grouped together represent plants grown concurrently. Bars denote the SD. Asterisks represent Student’s t-test significant differences (P<0.03). 5<n<25.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4493789&req=5

Figure 4: Growth of BdPAL RNAi1-1 and 1-3 plants compared with the WT or empty vector control (CTL). (A) Time course measurements of the longest leaf lengths and tallest culm heights of BdPAL RNAi1-1 plants. Arrows delineate the time points at which 50% of the spikelets could be seen emerging from the leaf whorl. (B) Average daily root growth of BdPAL RNAi1-1 and WT seedlings. n=48. (C, D) Average above-ground senesced biomass dry weight (C) and final culm heights (D). Columns grouped together represent plants grown concurrently. Bars denote the SD. Asterisks represent Student’s t-test significant differences (P<0.03). 5<n<25.
Mentions: To determine if BdPAL RNAi1-1 and 1-3 plants were affected in growth and development, lengths of leaves and culm heights were measured over time, revealing a slight but significant delay in growth of plants from both lines compared with the CTL (Fig. 4A; Supplementary Fig. S5A at JXB online). The culms of RNAi1-1 and 1-3 plants typically emerged and flowered a few days later than did CTL culms, suggestive of developmental delays. Moreover, RNAi1-1 and 1-3 culms grew to heights that, on average, were slightly shorter than the WT or CTL. RNAi knocked-down plants also accumulated slightly less above-ground biomass. Although the differences were not always statistically significant (Fig. 4B, C), they were significant in some experimental replicates, suggesting that the degree of PAL knockdown in these plants may be near the threshold of causing a yield penalty under controlled growth chamber conditions. More significantly, root growth assays revealed that BdPAL RNAi1-1 roots grew, on average, 60% more slowly than WT roots (Fig. 4B). While the underlying cause of the reduced root growth remains unclear, less extensive root systems could adversely impact above-ground growth.

Bottom Line: The cell walls of stems of BdPAL-knockdown plants had reductions of 43% in lignin and 57% in cell wall-bound ferulate, and a nearly 2-fold increase in the amounts of polysaccharide-derived carbohydrates released by thermochemical and hydrolytic enzymic partial digestion.RNA sequencing analyses revealed that the expression of genes associated with stress responses including ethylene biosynthesis and signalling were significantly altered in PAL knocked-down plants under non-challenging conditions.The data identify notable differences between the stress responses of these monocot pal mutants versus Arabidopsis (a dicot) pal mutants and provide insights into the challenges that may arise when deploying phenylpropanoid pathway-altered bioenergy crops.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Illinois State University, Normal, IL 61790 USA US Department of Energy Great Lakes Bioenergy Research Center, Madison, WI 53706, USA.

No MeSH data available.


Related in: MedlinePlus