Table 1. Mutant Strains Used in This Work.

Strain	Genotype	Phenotype	Ref.
WT 4γ	NIT1 NIT2 mt+a	Wild-type for photosynthesis and nitrogen assimilation; grows on nitrate and nitrite	[1]
nit1-137−	nit1-137 mt−a	Lacks NaR; cannot grow on nitrate, but grows on nitrite	[1]
nit2-124	nit2-124, mt+a	Lacks expression of NaR, NiR, and HANiT; cannot grow on nitrate nor nitrite	[1]
WT S24	nit1-137 nit2-124 mt−; results of multiple back-crosses of 137c mt+ and mt− strains	Our reference strain	[1]
		Lacks expression of NiR, NaR, and HANiT; cannot grow on nitrate nor nitrite	[1]
21gr	ΝΙΤ1 ΝΙΤ2 mt+	Wild-type for photosynthesis and nitrogen assimilation	CC-1690
M3	Δ(NII1 NRT2;2 NRT2;1 NAR2 NIT1) ::NIT1 ::(NRT2;2 NRT2;1) ::NAR2	Lacks NiR; cannot grow on nitrate nor nitrite	[2]
M4	Δ(NII1 NRT2;2 NRT2;1 NAR2 NIT1) ::NIT1	Lacks NiR and HANiT; cannot grow on nitrate nor nitrite	[2]
nit4-104	nit4-104 NIT1 NIT2 mt+	Lacks the MoCo cofactor of NaR and XOR; cannot grow on hypoxanthine, nitrate, or nitrite	[3] CC-2900
Tft5	nit1-305 ::NIT1 mt+	Complemented NaR mutant	[4]
dum22	nit1-137 nit2-124 mt− [Δcob, Δnd4]	Lacks mitochondrial cytochrome bc1 and NADH complexes.	[5]
nda2-RNAi	nda2RNAi nit1-137 nit2-124	Knockdown of the NDA2 gene	[6]
ptox2	ptox2::aphVIII nit1-137 nit2-124	Knockout the PTOX2 gene	[7]
{ΔpetB}	nit1-137 nit2-124 mt+ {ΔpetB}	Cytochrome b6f mutant deleted for the petB gene	[8]
ptox2 {ΔpetB}	ptox2::aphVIII nit1-137 nit2-124 {ΔpetB}	The ptox2 mutant carrying a deletion of the petB gene	[7]
tmFH8	mca1-6 ::MCA1-HA tca1-8 ::TCA1-Fl nit1-137 nit2-124 mt-	Expresses tagged versions of MCA1 and TCA1; otherwise wild-type for photosynthesis	[9]
mH ftsh1-1.2+	mca1-6 ::MCA1-HA ftsh1-1 nit1-137 nit2-124	Generated by cross mH mt− × ftsh1-1 mt+	[1]
mH {clpP-AUU}	mca1-6 ::MCA1-HA nit1-137 nit2-124 {clpP-AUU}	Generated by cross mH mt− × {clpP-AUU} mt+	[1]

By convention, chloroplast or mitochondrial genotypes, when relevant, follow the nuclear genotype and are written between brackets and braces, respectively, while parentheses indicate gene clusters, either deleted or inserted in the strain. CC numbers refer to strains obtained from the Chlamydomonas Resource Center (http://chlamycollection.org). References: [1] this work; [2] Navarro et al. (2000); [3] Chamizo-Ampudia et al. (2013); [4]; Kindle et al. (1989); [5] Remacle et al. (2006); [7] Houille-Vernes et al. (2011); [8] Kuras and Wollman (1994); [9] Boulouis et al. (2011).

^aGenerated from the cross WT-S24 mt⁻ × 21gr mt⁺ (CC-1690)