Physiological and Proteomic Responses of Mulberry Trees (Morus alba. L.) to Combined Salt and Drought Stress

Abstract

Intensive investigations have been conducted on the effect of sole drought or salinity stress on the growth of plants. However, there is relatively little knowledge on how plants, particularly woody species, respond to a combination of these two stresses although these stresses can simultaneously occur in the field. In this study, mulberry, an economically important resource for traditional medicine, and the sole food of domesticated silkworms was subjected to a combination of salt and drought stress and analyzed by physiological methods and TMT-based proteomics. Stressed mulberry exhibited significant alteration in physiological parameters, including root/shoot ratio, chlorophyll fluorescence, total carbon, and ion reallocation. A total of 577 and 270 differentially expressed proteins (DEPs) were identified from the stressed leaves and roots, respectively. Through KEGG analysis, these DEPs were assigned to multiple pathways, including carbon metabolism, photosynthesis, redox, secondary metabolism, and hormone metabolism. Among these pathways, the sucrose related metabolic pathway was distinctly enriched in both stressed leaves and roots, indicating an important contribution in mulberry under stress condition. The results provide a comprehensive understanding of the adaptive mechanism of mulberry in response to salt and drought stress, which will facilitate further studies on innovations in terms of crop performance.

Integrated Transcriptomic and Un-Targeted Metabolomics Analysis Reveals Mulberry Fruit (Morus atropurpurea) in Response to Sclerotiniose Pathogen Ciboria shiraiana Infection

“…Jasmonic acid and terpenoids play roles in resistance against Phytophthora cinnamomic in Zea mays roots [25]. Ethylene plays a positive role in adapting mulberry to cope with the drought and salinity condition [26]. Transcription factors are also an important factor of gene expression change [27].…”

“…Moreover, in trees displaying symptoms of wood decay, large amounts of lignans were observed [36]. Mulberry trees contain large quantities of flavonoids and other secondary metabolites, such as phenylpropanoids and alkaloids, which have wide roles in defenses against biotic and abiotic stresses [26] and have long been used in Chinese traditional medicine for human disease treatment [37]. A large number of flavonoid metabolites from mulberry fruit have been evaluated both in vitro and in vivo for their antioxidant activity [38], such as morcin N [39], anthocyanins [40], and so on.…”

Transcriptomic Analysis Reveals the Mechanism of Picea crassifolia Survival for Alpine Treeline Condition

“…α-Galactosidase (AGAL) is a key enzyme involved in the breakdown of RFOs [47], and plays a role in producing osmoprotectants that stabilize the membranes and protect cells against oxidative stress [48]. Moreover, α-glucosidase (AGLU) digests carbohydrates, including starch and stable sugar [46]. Thus, the increase in AGAL and AGLU expression observed in this study might help P. crassifolia to resist the cold stress at the higher elevations.…”

“…Thus, the increase in AGAL and AGLU expression observed in this study might help P. crassifolia to resist the cold stress at the higher elevations. However, the expression of GOLS1 (encoding galactinol synthase 1), which is the first committed enzyme in the RFO synthesis pathway [46], decreased with the increasing elevations. These results indicated that the RFO pathway might play a crucial role in the response of P. crassifolia to elevation changes.…”

“…RFOs, particularly raffinose, play a role in the acquisition of cold tolerance and other stress responses in many plant species [46,47]. α-Galactosidase (AGAL) is a key enzyme involved in the breakdown of RFOs [47], and plays a role in producing osmoprotectants that stabilize the membranes and protect cells against oxidative stress [48].…”