Chlorophyte algae having improved productivity
The invention involves mutant or recombinant Chlorophyte algal organisms that have a genetic modification in a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). In one embodiment the Chlorophyte organisms are Trebouxiophyte algae that are diploid or polyploid for a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). The mutant organisms can have a genetic modification in one allele of the gene but not in another allele of the gene. The mutant or algal organisms have higher biomass and lipid productivity. Additional mutant or algal organisms are disclosed that also have a genetic modification to one or more genes encoding a light harvesting chlorophyll a/b (binding) protein.
1 . A mutant Trebouxiophyte algal organism comprising:
a disruption in a first allele of a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein having at least 90% sequence identity to either SEQ ID NO: 2 or 4, and comprising a second, active allele of the gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein having at least 90% sequence identity to the other of SEQ ID NO: 2 or 4, that does not comprise a disruption, and wherein the first allele and the second allele are not the same allele.
2 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has at least 5% greater biomass productivity than a corresponding control organism not having the disruption of the first allele of the gene encoding a chloroplastic SRP43 protein.
3 . The mutant Trebouxiophyte algal organism of claim 2 wherein the first allele of the gene encodes a cpSRP43 protein having at least 90% sequence identity to SEQ ID NO: 2 and the second allele encodes a cpSRP43 protein having at least 90% sequence identity to SEQ ID NO: 4.
4 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism is of the genus Picochlorum.
5 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a PSII σ450 value of less than 300 A 2 , and a PSII σ520 value of less than 100 A 2 .
6 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a PSI σ450 value of less than 500 A 2 , and a PSI σ520 value of less than 150 A 2 .
7 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a biomass productivity at least 7% higher than a corresponding control organism.
8 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a ratio of PSI/PSII antenna cross section of less than 1.5.
9 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a Chl a:b ratio of greater than 6.0.
10 . The mutant Trebouxiophyte algal organism of claim 2 wherein the organism has:
a PSII σ450 value of less than 300 A 2 and a PSII σ520 value of less than 100 A 2 , or
a PSI σ450 value of less than 500 A 2 , and a PSI σ520 value of less than 150 A 2 , or
a PSI/PSII value of less than 0.65 and a Chl a:b ratio of greater than 6.0.
11 . The mutant Trebouxiophyte algal organism of claim 3 wherein the organism is diploid.
12 . The mutant Trebouxiophyte algal organism of claim 3 wherein the organism is polyploid.
13 . The mutant Trebouxiophyte algal organism of claim 2 further comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI comprising at least 90% sequence identity to any one of SEQ ID NOs: 7-12.
14 . The mutant Trebouxiophyte algal organism of claim 1 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein LHCP-11 of PSI, and/or a gene encoding a light harvesting complex LHCP-21 of PSI.
15 . The mutant Trebouxiophyte algal organism of claim 1 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 21, or a disruption of a gene encoding a light harvesting complex of PSI having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 22.
16 . The mutant Trebouxiophyte algal organism of claim 2 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI having a sequence with at least 90% sequence identity to SEQ ID NO: 7, and a disruption of a gene encoding a light harvesting complex of PSI having a sequence with at least 90% sequence identity to SEQ ID NO: 8.
17 . The mutant Trebouxiophyte algal organism of claim 16 having a lipid productivity at least 4% higher than a corresponding control algal organism.
18 . The mutant Trebouxiophyte algal organism of claim 16 wherein the mutant Trebouxiophyte algal organism is a member of the genus Pichochlorum.
19 . A biomass comprising the mutant Trebouxiophyte algal organism of claim 1 .
20 . A biomass comprising the mutant Trebouxiophyte algal organism of claim 11 .
21 . A method of producing a lipid composition comprising culturing the mutant Trebouxiophyte algal organism of claim 1 in a culture medium to produce a biomass composition containing lipids.
22 . The method of claim 21 further comprising harvesting a lipid product from the biomass composition.
23 . A method of attenuating a pigment composition in a mutant Trebouxiophyte algal organism comprising:
cultivating the mutant Trebouxiophyte algal organism of claim 1 to thereby attenuate the pigment in the mutant Trebouxiophyte algal organism.
24 . The method of claim 23 wherein the mutant Trebouxiophyte algal organism is a member of the genus Picochlorum.
25 . The method of claim 23 wherein the disruption is generated by exposing the mutant Trebouxiophyte algal organism to uv light and/or gamma radiation.
26 . The method of claim 23 wherein the mutant Trebouxiophyte algal organism further comprises a disruption of a gene encoding a light harvesting (binding) protein having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 21 or SEQ ID NO: 22.