Jialin Guo

For its rapid growth, high yield, and broad adaptability, Arundo donax is widely used in various applications, yielding considerable economic and ecological benefits. However, widespread cultivation is challenging because A. donax can only be propagated asexually. In this study, a tissue culture method was developed using the clustered bud proliferation pathway. The explant type, disinfection method, induction medium, proliferation medium, and rooting medium were optimized to efficiently harvest high-quality A. donax seedlings. Using axillary buds with whole cane fragments as the most suitable explants, they were first sterilized with 75% alcohol for 30 s and then disinfected with 0.1% mercuric chloride for 5 min. 97.8% of explants could successfully form clustered buds on Murashige and Skoog (MS) medium supplemented with 5.0 mg/L 6-benzylaminopurine (6-BA) and 1.0 mg/L 3-indolebutyric acid (IBA). Each individual bud achieved efficient propagation with a proliferation coefficient as high as 33.3 on MS medium supplemented with 4.0 mg/L 6-BA and 1.0 mg/L IBA. In addition, all buds were capable of rooting on 1/2 MS medium supplemented with 0.5 mg/L 1-naphthaleneacetic acid (NAA). The resultant rooted seedlings survived and developed into plantlets, averaging 44.84 cm in height and 2.54 mm in thickness, following a 30-day acclimation period. This protocol provides a robust foundation for the large-scale, high-quality propagation of A. donax, supporting its broader application in ecological restoration and bioresource industries.

Arundo donax exhibits strong comprehensive stress resistance and high levels of crude protein and crude fiber, making it an ideal perennial forage crop. It adapts to various abiotic stresses and serves as a new model for studying plant stress response mechanisms. A. donax frequently encounters diverse environmental stresses during agricultural production, including drought, waterlogging, and temperature extremes. However, the response mechanisms of A. donax to multiple stresses remains elusive. By analyzing publicly available transcriptome data, we identified 9089, 19,272, and 8585 differentially expressed genes (DEGs) and 742 DEGs shared in the leaves of A. donax under drought, waterlogging, and cold conditions. The data showed that A. donax exhibits differential activation patterns in endogenous hormone signaling (jasmonate/gibberellin), energy metabolism (UDP-glucosyltransferase), and nitrogen metabolism pathways (acyltransferase) under these stresses. DEGs involved in the nitrogen metabolism and phenylpropanoid metabolism pathways were significantly enriched, while the gene expression patterns of these pathways varied among the drought, waterlogging, and cold stress conditions. Different stresses could affect the nitrogen accumulation in A. donax leaves. In addition, pairwise DEG comparisons indicated active roles of antioxidant defense and photosynthetic system in multiple stress responses. Physiological measurements validated these transcriptional changes: the activities of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD)) increased significantly, minimizing oxidative damage. Meanwhile, the photosynthetic pigments content also decreased in response to the three stresses. Soluble sugars, pyruvate, malate, and citrate, which are involved in energy metabolism in the leaves of A. donax, accumulated to sustain themaintenance of the plant’s own energy metabolism. In conclusion, our study revealed the transcriptome-based regulatory network related with synergistic response mechanisms of A. donax leaves under multiple stress conditions.

Arundo donax (family: Poaceae) is a perennial rhizomatous plant with considerable economic and ecological benefits. The plant is characterized by its fast growth, high yield, wide adaptability, and strong disease resistance. However, widespread cultivation is difficult because A. donax can only be asexually propagated. This study tested the efficacy of an aqua-based culture method with short duration and high rooting rate. The aqua-based culture protocol involved treating cane fragments with the commercial broad-spectrum rooting powder ABT-1 (No. 1 of the ABT series) at 100 mg/L for 24 h, followed by culturing in tap water for 19 days. We found that plant materials sampled from September to February of the following year were more suitable for aqua-based culturing than materials sampled from other months. Nodes on different parts of the cane did not vary significantly in the ability to form seedlings. The rooting percentage reached >95% after only 20 days, while the sprouting percentage was >93%. The seedlings obtained were strong, with high survival rates during cultivation and acclimation. No strict requirements for the growing media were necessary to achieve these results. In conclusion, this study provides an empirical foundation for a technique that could facilitate the factory production of high-quality A. donax seedlings.

Arundo donax is widely used as an ornamental plant in landscape gardening because of its adaptability to varying degrees of waterlogged conditions. However, to date, little information is available about the adaptive mechanism of A. donax under waterlogging stress. The results showed that long-term mild waterlogging efficiently induced the formation of adventitious roots (ARs) and further promoted root aerenchyma development, and that the activity of antioxidant enzymes (SOD, POD, and CAT) in Ars also was greatly enhanced after waterlogging. At the transcriptomic level, the expression of genes related to apoptosis, the regulation of cell division, ethylene biosynthesis, alginate synthesis, auxin signaling pathways, and anaerobic respiration was mostly up-regulated after the occurrence of waterlogging stress but genes involved in the abscisic acid signaling pathways were partly down-regulated, which indicated a preferential and favorable transcriptional response in regulating adventitious root development. Taken together, this study definitely advances our knowledge of the morphological, physiological, and transcriptomic responses of A. donax under waterlogging stress and sheds new lights on its adaptive mechanisms.

Cytoplasmic male sterility (CMS) is a complex phenomenon in plants, rendering them unable to produce functional pollen. In general, this is caused by an abnormal or dysfunctional mitochondrial genome. In wheat, however, the systematic structural characteristics of the mitochondrial genome from the CMS line, vis-à-vis its maintainer line, are rarely reported. Here, we identified the morphological characteristics, sequenced, assembled, and characterized the complete mitogenomes of the wheat B-type CMS line (B) and its maintainer line (YS9). The morphological results indicated that the B likely undergoes binucleate microspore abortion. The B and YS9 genomes were assembled into a typical circular molecule 452,794 and 452,453 bp in length, respectively, comprising 34 protein-coding genes (PCGs), 3 ribosomal RNA genes (rRNAs), and 16 transfer RNA genes (tRNAs). The codon usage analysis revealed leucine (Leu) and serine (Ser) as the most frequently used amino acid residues in the B and YS9 mitochondrial proteins. In particular, we uncovered a specific ORF2718, whose length of 501 bp was more 30 bp than that of the atp8 gene in the B genome, which perhaps could affect normal function of ATP8. Further, the existence of SNPs at the atp6 gene is probably associated with the CMS mechanism. This study suggests that sequencing and comparing the genomic features of the B and YS9 mitogenomes provides not only an important opportunity to conduct further genomic breeding studies, but also valuable information for future evolutionary and molecular studies of CMS in wheat.

The multi-ovary trait of wheat inbred line DUOII is controlled by a dominant gene whose expression can be suppressed by the heterogeneous cytoplasm of TeZhiI (TZI), another inbred line with the nucleus of common wheat and the cytoplasm of Aegilops. DUOII (♀) × TZI (♂) shows multi-ovary trait, while TZI (♀) × DUOII (♂) shows mono-ovary. To elucidate the molecular mechanism regulating heterogeneous cytoplasmic suppression of the multi-ovary gene, we performed an untargeted metabolomic analysis of 2–6 mm young spikes of reciprocal crosses between DUOII and TZI at the critical stage of additional pistil primordium development. We identified 198 annotated differentially expressed metabolites and analyzed them according to their biological functions. The results showed that these metabolites had obvious functional pathways mainly implicated in amino acid, carbohydrate, nicotinate and nicotinamide, and purine metabolism and isoquinoline alkaloid biosynthesis. We also found that shikimate, phosphoglycolic acid, nicotinamide, guanine, and xanthine might play essential roles in cytoplasmic suppression of multi-ovary trait. Chloroplast metabolism was also implicated in the nuclear-cytoplasmic effect of the multi-ovary gene. The findings provide solid theoretical and empirical foundations for future studies elucidating the mechanisms controlling heterogeneous cytoplasmic suppression of the nuclear multi-ovary gene in wheat.

Multi-ovary wheat is a unique variety of wheat that has one to three pistils and three stamens, and can stably set one to three grains in each floret. By observing the developmental process of additional pistils, we found that the additional pistil was derived from a protrusion generated at the base of the main pistil, between the frontal stamen and lateral stamen. The additional pistil’s development was greatly delayed compared with the main pistil at an early stage. However, after the awn exposed stage, it developed very rapidly to a mature pistil within the maturity time of the main pistil. Generally, the grains originating from additional pistils were smaller than the grains from the main pistil. By studying the penetrance and germination conditions of multi-ovary wheat, we found that no matter which ovary the grains originated from, they had the same penetrance. However, the germination ability of grains generated from the main pistil was significantly higher than that of grains from additional pistils. Our results showed that multi-ovary wheat was an excellent variety, not only for studying the mechanisms of the multi-ovary trait and floral development in wheat, but also for improving the propagation coefficient and promoting the progress of wheat breeding. This paper lays a theoretical foundation for the practical application of multi-ovary trait in hybrid wheat; our results could be implemented in fostering future breeding activities focussed on the development of high yield wheat cultivars.