Title: Increased drought tolerance in plants engineered for low lignin and low xylan content

Abstract

We previously developed several strategies to engineer plants to produce cost-efficient biofuels from plant biomass. Engineered Arabidopsis plants with low xylan and lignin content showed normal growth and improved saccharification efficiency under standard growth conditions. However, it remains to be determined whether these engineered plants perform well under drought stress, which is the primary source of abiotic stress in the field. Upon exposing engineered Arabidopsis plants to severe drought, we observed better survival rates in those with a low degree of xylan acetylation, low lignin, and low xylan content compared to those in wild-type plants. Increased pectic galactan content had no effect on drought tolerance. The drought-tolerant plants exhibited low water loss from leaves, and drought-responsive genes (RD29A, RD29B, DREB2A) were generally up-regulated under drought stress, which did not occur in the well-watered state. When compared with the wild type, plants with low lignin due to expression of QsuB, a 3-dehydroshikimate dehydratase, showed a stronger response to abscisic acid (ABA) in assays for seed germination and stomatal closure. The low-lignin plants also accumulated more ABA in response to drought than the wild-type plants. On the contrary, the drought tolerance in the engineered plants with low xylan content and low xylanmore » acetylation was not associated with differences in ABA content or response compared to the wild type. Surprisingly, we found a significant increase in galactose levels and sugar released from the low xylan-engineered plants under drought stress. This work shows that plants engineered to accumulate less lignin or xylan are more tolerant to drought and activate drought responses faster than control plants. This is an important finding because it demonstrates that modification of secondary cell walls does not necessarily render the plants less robust in the environment, and it shows that substantial changes in biomass composition can be achieved without compromising plant resilience.« less

Authors:

Yan, Jingwei; Aznar, Aude; Chalvin, Camille; Birdseye, Devon S.; Baidoo, Edward E. K.; Eudes, Aymerick; Shih, Patrick M.; Loqué, Dominique; Zhang, Aying; Scheller, Henrik V.

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• Search DOE PAGES for ORCID "0000-0002-6702-3560"

Publication Date:

Wed Jul 18 00:00:00 EDT 2018

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); China Scholarship Council (CSC)

OSTI Identifier:

1618727

Alternate Identifier(s):

OSTI ID: 1465462

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Published Article

Journal Name:

Biotechnology for Biofuels

Additional Journal Information:

Journal Name: Biotechnology for Biofuels Journal Volume: 11 Journal Issue: 1; Journal ID: ISSN 1754-6834

Publisher:

Springer Science + Business Media

Country of Publication:

Netherlands

Language:

English

Subject:

60 APPLIED LIFE SCIENCES; 09 BIOMASS FUELS; drought tolerance; abscisic acid; cell walls; lignin; xylan; biofuel; synthetic biology; Arabidopsis thaliana