The novel protein domain plays an important role in photosynthetic system II assembly and angiosperm photoautotroph

Recently, Mo Xiaorong's research group from the Institute of Plant Biology, College of Life Sciences, Zhejiang University, published a report entitled " A novel protein domain is important for photosystem II complex assembly and photoautotrophic growth in angiosperms"
.
The study discovered a new domain CLS domain on the TROL2 gene; It was revealed that this domain plays an important role in the assembly of photosystem II complexes and is necessary for photoautotrophs in angiosperms.
At the same time, the evolutionary origin
of this domain is elucidated.

TROL (Thylakoid rhodanese-like protein) is capable of converting leaf-type ferrostatin: NADP+ oxidoreductase LFNR (Leaf-type Ferredoxin–NADP+).
oxidoreductase) anchors to the
thylakoid membrane.
By comparing the functions of a pair of rice homologous genes TROL1 and TROL2, they found that both were mainly expressed in leaves, localized on chloroplast thylakoid membranes, and both could interact with LFNR
.
However, TROL1 and TROL2 in rice showed a completely different phenotype, and the ostrol1 mutant phenotype was similar to the wild type, but ostrol2 Mutants, however, will have a phenotype
of yellowing and death at the seedling stage.
The OsTROL2 promoter drives OsTROL2 to restore the ostrol2 mutant phenotype, but with the same promoter-driven OsTROL1 The inability to revert the ostrol2 mutant phenotype suggests that OsTROL2 has a function
that is more important for plant survival than OsTROL1.

The study of the structure and assembly of photosystem II (PSII.
) complexes is of great significance
for elucidating the mechanism of photosynthesis.
For the first time, they reported the function of TROL2 in the assembly of PSII compounds, which is what distinguishes OsTROL2 from OsTROL1
.
They also revealed the molecular mechanism by which TROL2 is involved in the assembly of PSII complexes: TROL2 is able to form complexes with LPA2 PsbI, PsbL, and PsbZ interact to facilitate the assembly
of PSII complexes.

Interestingly, they also identified a new CLS (Chlorotic lethal seedling) domain at the N-terminal of TROL2, which was shown to contain only by truncated recovery experiments The CLS domain of 45 amino acids is sufficient to exert the important functions
of TROL2 in PSII assembly and photoautotroph.
Based on the results of phylogenetic tree analysis, they speculated that TROL2 evolved through the TROL1 gene replication and its N-terminal sequence before the emergence of seed plants CLS domain, thus obtaining new features
.
The absence of TROL2 in soybean, Arabidopsis thaliana and maize will show yellowing at the seedling stage and death, indicating that the function of TROL2 in angiosperms is very conserved
.
THEY ALSO COMPARED THE FUNCTIONS BETWEEN THE LOWER PLANT (LAND MONEY) TROL AND THE ANGIOSPERM TROL2, ASKING AN INTERESTING QUESTION: "WHY IS TROL2 THE FOUNDATION.
" Required for photoautotrophic survival of angiosperms, but not in algae, mosses and ferns TROL2？ ”

These findings provide a good example of the generation of functional genes through gene replication and new functionalization in the evolutionary process, and have important theoretical value
for improving the molecular mechanism of photosynthetic complex assembly and the evolution of angiosperms.

TROL2 is able to form complexes with LPA2 and interact with PsbI, PsbL, and PsbZ to promote Diagram of the working model of the assembly of the PSII complex.

The paper is co-authored by Li Wei and Guo Jiangfan, two doctoral students who have graduated from Zhejiang University, and Professor Mo Xiaorong of Zhejiang University is the corresponding author
.
At the same time, Dr.
Han Xue, Dr.
Huang Shitang, Prof.
Bosheng Li, Prof.
He Hang, Prof.
He Yi, Associate Professor of Zhejiang A&F University, Dr.
Xu Jiming, Dr.
Liu Yu, Prof.
Yunrong Wu, Prof.
Shou Huixia, Prof.
Zhongchang Wu, Professor Mao Chuanyu also participated in the research work
of the paper.
The project was supported by the National Key R&D Program of China and the Key Project of Zhejiang Natural Science Foundation.

Original link: https://linkinghub.
elsevier.
com/retrieve/pii/S1674205222004518