10.5061/DRYAD.NGF1VHHRC
Martin-Avila, Elena
Australian National University
Lim, Yi-leen
Australian National University
Birch, Rosemary
Australian National University
Dirk, Lynnette
University of Kentucky
Buck, Sally
Australian National University
Rhodes, Timothy
Australian National University
Sharwood, Robert
Australian National University
Kapralov, Maxim
Newcastle University
Whitney, Spencer
Australian National University
Modifying plant photosynthesis and growth via simultaneous chloroplast
transformation of Rubisco large and small subunits
Dryad
dataset
2020
2020-08-10T00:00:00Z
2020-08-10T00:00:00Z
en
69392 bytes
2
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Engineering improved Rubisco poses a crucial strategy for enhancing
photosynthesis but is challenged by the alternate locations of the
plastome rbcL gene and nuclear RbcS genes. Here we develop a RNAi-RbcS
Nicotiana tabacum (tobacco) master-line, tobRrΔS, amenable to rbcL-rbcS
co-engineering by chloroplast transformation. Four tobacco genotypes
coding alternative rbcS genes and adjoining 5ˈ-intergenic sequences
revealed Rubisco production was highest in the lines incorporating a rbcS
gene whose codon use and 5ˈUTR matched rbcL. These lines produced up to
50% the wild-type Rubisco content. Additional tobacco lines coding potato
rbcL-rbcS operons examined how the differing mesophyll made small subunits
(pS1, pS2, pS3) or the trichome pST-25 subunit influenced Rubisco
biogenesis, catalysis, leaf physiology and plant growth. Rubisco levels
were ~15% lower in leaves expressing pS3 relative to those producing pS1,
pS2, and pST. However, the pS3-subunit increased carboxylation rate
(kcatC) by 13% and carboxylation efficiency (CE, kcatC divided by the Km
for CO2) by 17% relative to the pS1 and pS2 subunits as a result of the
βa-βb loop substitutions Asn-55-His and Lys-57-Ser. By contrast tobacco
photosynthesis and growth were most impaired in lines producing the
pST-subunit that reduced CE and CO2/O2 specificity of potato Rubisco by
40% and 15% respectively.