Transgenic plants with increased photosynthesis efficiency and growth

Inventors

Long, Stephen P. • Kromdijk, Johannes • Glowacka, Katarzyna • Niyogi, Krishna K. • Leonelli, Laurie Beth • Gabilly, Stephane T.

Assignees

University of California, San Diego • University of Illinois System

Abstract

The present disclosure provides a transgenic plant comprising one or more nucleotide sequences encoding polypeptides selected from photosystem II subunit S (PsbS), zeaxanthin epoxidase (ZEP), and violaxanthin de-epoxidase (VDE), operably linked to at least one expression control sequence. Expression vectors for making transgenic plants, and methods for increasing biomass production and/or carbon fixation and/or growth in a plant comprising increasing expression of at least one of PsbS, ZEP and VDE polypeptides are also provided.

Core Innovation

The invention relates to genetically modified higher plants that are tracheophytes and comprise at least endogenous levels of an endogenous photosystem II subunit S (PsbS) polypeptide. Expression of both a zeaxanthin epoxidase (ZEP) polypeptide and a violaxanthin de-epoxidase (VDE) polypeptide is increased compared to expression in a control plant without the genetic modifications grown under the same conditions.

The genetic modifications increase VDE expression and ZEP expression by expressing transfected nucleotide sequences encoding the respective polypeptides and/or by genetic modification in a promoter of a nucleotide sequence encoding the respective polypeptides. The invention is directed to transgenic or engineered plants expressing heterologous photosystem II subunit S (PsbS) and xanthophyll-cycle enzymes, including ZEP and VDE, using expression vectors and promoter control for increased expression of both polypeptides.

The documented embodiments describe altered non-photochemical quenching (NPQ) dynamics and improved photoprotection in VPZ transgenic plant lines compared to wild-type (WT), with faster qE/qZ NPQ relaxation and faster recovery of PSII operating efficiency after fluctuating/high-light transitions. Under fluctuating light, VPZ lines maintain higher ΦPSII-max and ΦCO2-max versus WT and show reduced xanthophyll de-epoxidation, with lower DES and less zeaxanthin/antheraxanthin accumulation.

Greenhouse growth assessments indicate increased plant height, leaf area, and total dry biomass, including stem, leaf, and root dry weight, in VPZ lines relative to WT. The disclosure further encompasses variants defined by sequence identity and conserved domains, and constructs and expression control sequences configured to achieve specified expression and VDE:ZEP expression relationships.

Claims Coverage

The provided independent claims cover a genetically modified tracheophyte higher plant with increased expression of both ZEP and VDE relative to a control plant, while maintaining at least endogenous PsbS and specifying the mechanisms for increasing each enzyme’s expression.

Overall claim coverage centers on a tracheophyte higher plant engineered to increase ZEP and VDE polypeptide expression relative to a matched control plant, while requiring at least endogenous PsbS levels and defining increased expression for each polypeptide via transfected nucleotide sequences and/or promoter modifications.

Stated Advantages

Documented Applications