Exogenous methylglyoxal alleviates drought-induced 'plant diabetes' and leaf senescence in maize.

Drought-induced leaf senescence is associated with high sugar levels, which bears some resemblance to the syndrome of diabetes in humans; however, the underlying mechanisms of such 'plant diabetes' on carbon imbalance and the corresponding detoxification strategy are not well understood. Here, we investigated the regulatory mechanism of exogenous methylglyoxal (MG) on 'plant diabetes' in maize plants under drought stress applied via foliar spraying during the grain-filling stage. Exogenous MG delayed leaf senescence and promoted photoassimilation, thereby reducing the yield loss induced by drought by 14%. Transcriptome and metabolite analyses revealed that drought increased sugar accumulation in leaves through inhibition of sugar transporters that facilitate phloem loading. This led to disequilibrium of glycolysis and overaccumulation of endogenous MG. Application of exogenous MG up-regulated glycolytic flux and the glyoxalase system that catabolyses endogenous MG and glycation end-products, ultimately alleviating 'plant diabetes'. In addition, the expression of genes facilitating anabolism and catabolism of trehalose-6-phosphate was promoted and suppressed by drought, respectively, and exogenous MG reversed this effect, implying that trehalose-6-phosphate signaling in the mediation of 'plant diabetes'. Furthermore, exogenous MG activated the phenylpropanoid biosynthetic pathway, promoting the production of lignin and phenolic compounds, which are associated with drought tolerance. Overall, our findings indicate that exogenous MG activates defense-related pathways to alleviate the toxicity derived from 'plant diabetes', thereby helping to maintain leaf function and yield production under drought.

[The rules of acupoint selection of acupuncture and moxibustion for scrofula in ancient times].

Based on data mining technology, the rules of acupoint selection of acupuncture-moxibustion for scrofula in ancient times were analyzed. The relevant articles of acupuncture and moxibustion for scrofula were searched in the Chinese Medical Code, and the original article, acupoint name, acupoint characteristic, and acupoint meridian tropism, etc. were screened and extracted. The Microsoft Excel 2019 was used to establish a acupoint prescription database, and the frequency of acupoints as well as their meridian tropism and characteristics were analyzed. The SPSS21.0 was applied to perform cluster analysis of acupuncture prescriptions; the SPSS Modeler 18.0 was used to perform the association rules analysis of the neck and the chest-armpit acupoints, respectively. As a result, 314 acupuncture prescriptions were extracted, including 236 single-acupoint prescriptions and 78 multiple-acupoints prescriptions (53 for neck and 25 for chest-armpit). A total of 54 acupoints were involved, with a total frequency of 530. The top 3 commonly-used acupoints were Tianjing (TE 10), Zulinqi (GB 41) and Taichong (LR 3); the most commonly-used meridians were hand shaoyang meridian, foot shaoyang meridian, hand yangming meridian and foot yangming meridian; the most commonly-used special acupoints were he-sea points and shu-stream points. The cluster analysis obtained 6 clusters, and the association rule analysis obtained that the core prescriptions of the neck were Quchi (LI 11), Jianyu (LI 15), Tianjing (TE 10) and Jianjing (GB 21), while the core prescriptions of the chest-armpit were Daling (PC 7), Yanglingquan (GB 34), Danzhong (CV 17), Jianjing (GB 21), Waiguan (TE 5), Zhigou (TE 6), Yuanye (GB 22) and Zhangmen (LR 13). The core prescriptions obtained from association rule analysis by difference areas were basically consistent with those by cluster analysis of total prescriptions.