Proteome analysis of bermudagrass stolons and rhizomes provides new insights into the adaptation of plant stems to aboveground and underground growth

Review: Nitrogen acquisition, assimilation, and seasonal cycling in perennial grasses

Perennial grasses seasonal nitrogen (N) cycle extends the residence and reuse time of N within the plant system, thereby enhancing N use efficiency. Currently, the mechanism of N metabolism has been extensively examined in model plants and annual grasses, and although perennial grasses exhibit similarities, they also possess distinct characteristics. Apart from assimilating and utilizing N throughout the growing season, perennial grasses also translocate N from aerial parts to perennial tissues, such as rhizomes, after autumn senescence. Subsequently, they remobilize the N from these perennial tissues to support new growth in the subsequent year, thereby ensuring their persistence. Previous studies indicate that the seasonal storage and remobilization of N in perennial grasses are not significantly associated with winter survival despite some amino acids and proteins associated with low temperature tolerance accumulating, but primarily with regrowth during the subsequent spring green-up stage. Further investigation can be conducted in perennial grasses to explore the correlation between stored N and dormant bud outgrowth in perennial tissues, such as rhizomes, during the spring green-up stage, building upon previous research on the relationship between N and axillary bud outgrowth in annual grasses. This exploration on seasonal N cycling in perennial grasses can offer valuable theoretical insights for new perennial grasses varieties with high N use efficiency through the application of gene editing and other advanced technologies.

Physiological and Proteomic Analyses of mtn1 Mutant Reveal Key Players in Centipedegrass Tiller Development

Tillering directly determines the seed production and propagation capacity of clonal plants. However, the molecular mechanisms involved in the tiller development of clonal plants are still not fully understood. In this study, we conducted a proteome comparison between the tiller buds and stem node of a multiple-tiller mutant mtn1 (more tillering number 1) and a wild type of centipedegrass. The results showed significant increases of 29.03% and 27.89% in the first and secondary tiller numbers, respectively, in the mtn1 mutant compared to the wild type. The photosynthetic rate increased by 31.44%, while the starch, soluble sugar, and sucrose contents in the tiller buds and stem node showed increases of 13.79%, 39.10%, 97.64%, 37.97%, 55.64%, and 7.68%, respectively, compared to the wild type. Two groups comprising 438 and 589 protein species, respectively, were differentially accumulated in the tiller buds and stem node in the mtn1 mutant. Consistent with the physiological characteristics, sucrose and starch metabolism as well as plant hormone signaling were found to be enriched with differentially abundant proteins (DAPs) in the mtn1 mutant. These results revealed that sugars and plant hormones may play important regulatory roles in the tiller development in centipedegrass. These results expanded our understanding of tiller development in clonal plants.

Proteome-wide analyses reveal diverse functions of protein acetylation and succinylation modifications in fast growing stolons of bermudagrass (Cynodon dactylon L.)

BACKGROUND

Bermudagrass (Cynodon dactylon L.) is an important warm-season turfgrass species with well-developed stolons, which lay the foundation for the fast propagation of bermudagrass plants through asexual clonal growth. However, the growth and development of bermudagrass stolons are still poorly understood at the molecular level.

RESULTS

In this study, we comprehensively analyzed the acetylation and succinylation modifications of proteins in fast-growing stolons of the bermudagrass cultivar Yangjiang. A total of 4657 lysine acetylation sites on 1914 proteins and 226 lysine succinylation sites on 128 proteins were successfully identified using liquid chromatography coupled to tandem mass spectrometry, respectively. Furthermore, 78 proteins and 81 lysine sites were found to be both acetylated and succinylated. Functional enrichment analysis revealed that acetylated proteins regulate diverse reactions of carbohydrate metabolism and protein turnover, whereas succinylated proteins mainly regulate the citrate cycle. These results partly explained the different growth disturbances of bermudagrass stolons under treatment with sodium butyrate and sodium malonate, which interfere with protein acetylation and succinylation, respectively. Moreover, 140 acetylated proteins and 42 succinylated proteins were further characterized having similarly modified orthologs in other grass species. Site-specific mutations combined with enzymatic activity assays indicated that the conserved acetylation of catalase and succinylation of malate dehydrogenase both inhibited their activities, further implying important regulatory roles of the two modifications.

CONCLUSION

In summary, our study implied that lysine acetylation and succinylation of proteins possibly play important regulatory roles in the fast growth of bermudagrass stolons. The results not only provide new insights into clonal growth of bermudagrass but also offer a rich resource for functional analyses of protein lysine acetylation and succinylation in plants.

A High-Quality Haplotype-Resolved Genome of Common Bermudagrass (Cynodon dactylon L.) Provides Insights Into Polyploid Genome Stability and Prostrate Growth

Common bermudagrass (Cynodon dactylon L.) is an important perennial warm-season turfgrass species with great economic value. However, the reference genome is still deficient in C. dactylon, which severely impedes basic studies and breeding studies. In this study, a high-quality haplotype-resolved genome of C. dactylon cultivar Yangjiang was successfully assembled using a combination of multiple sequencing strategies. The assembled genome is approximately 1.01 Gb in size and is comprised of 36 pseudo chromosomes belonging to four haplotypes. In total, 76,879 protein-coding genes and 529,092 repeat sequences were annotated in the assembled genome. Evolution analysis indicated that C. dactylon underwent two rounds of whole-genome duplication events, whereas syntenic and transcriptome analysis revealed that global subgenome dominance was absent among the four haplotypes. Genome-wide gene family analyses further indicated that homologous recombination-regulating genes and tiller-angle-regulating genes all showed an adaptive evolution in C. dactylon, providing insights into genome-scale regulation of polyploid genome stability and prostrate growth. These results not only facilitate a better understanding of the complex genome composition and unique plant architectural characteristics of common bermudagrass, but also offer a valuable resource for comparative genome analyses of turfgrasses and other plant species.