Transcriptional and Metabolic Responses of Maize Shoots to Long-Term Potassium Deficiency

Abstract

Potassium is important for plant growth and crop yield. However, the effects of potassium (K+) deficiency on silage maize biomass yield and how maize shoot feedback mechanisms of K+ deficiency regulate whole plant growth remains largely unknown. Here, the study aims to explore the maize growth, transcriptional and metabolic responses of shoots to long-term potassium deficiency. Under the K+ insufficiency condition, the biomass yield of silage maize decreased. The transcriptome data showed that there were 922 and 1,107 differential expression genes in DH605 and Z58, respectively. In the two varieties, 390 differently expressed overlapping genes were similarly regulated. These genes were considered the fundamental responses to K+ deficiency in maize shoots. Many stress-induced genes are involved in transport, primary and secondary metabolism, regulation, and other processes, which are involved in K+ acquisition and homeostasis. Metabolic profiles indicated that most amino acids, phenolic acids, organic acids, and alkaloids were accumulated in shoots under K+ deficiency conditions and part of the sugars and sugar alcohols also increased. It revealed that putrescine and putrescine derivatives were specifically accumulated under the K+ deficiency condition, which may play a role in the feedback regulation of shoot growth. These results confirmed the importance of K+ on silage maize production and provided a deeper insight into the responses to K+ deficiency in maize shoots.

Integrated Physiological and Metabolomic Analyses Reveal the Differences in the Fruit Quality of the Blueberry Cultivated in Three Soilless Substrates

“…This study revealed that the content of Phe in the FBR-treated group fruit increased 2.33-fold compared with that in the FPR (CK) group, which may promote the synthesis of polyphenols in the FBR treatment group. Additionally, the highest K content in the FBR substrate may also play an important role in the metabolism of amino acids in the fruit, since K is closely related to the biosynthesis, transformation, and distribution of metabolites [ 56 , 57 ]. Sugar is an indispensable part of the plant growth process; it not only provides a carbon skeleton for plants, but also increases the resistance of plants [ 10 , 58 ].…”

Integrated transcriptomic and metabolomic analyses reveal key metabolic pathways in response to potassium deficiency in coconut (Cocos nucifera L.) seedlings

“…The expression of genes related to organic and amino acid metabolism was significantly altered in oats under P deficiency ( Wang et al., 2018 ). In maize seedlings under K + deficiency stress, MAPK signaling pathway-plant, signal transduction mechanisms, plant hormone signal transduction, and amino acid transport and metabolism were the mainy enriched pathways, and related gene expression was significantly altered ( Xiong et al., 2022 ) In our study, in coconut seedling leaves under K + deficiency stress, “MAPK signaling pathway-plant”, “signal transduction mechanisms”, “plant hormone signal transduction”, “amino acid transport and metabolism”, “plant-pathogen interaction”, “starch and sucrose metabolism”, “spliceosome”, “endocytosis”, “ABC transporters”, “fatty acid elongation”, and “protein kinase/protein domain” pathways were affected. In particular, genes related to “MAPK signaling pathway-plant”, “signal transduction mechanisms”, “plant hormone signal transduction”, “amino acid transport and metabolism” pathways were significantly down-regulated ( Supplementary Tables 7, 8 ).…”

“…In different substances, whether up-or down-regulated, each metabolite, whether up- or down-regulated, plays a different role and plays a very important role in response to low-K + stress. For example, sugars such as raffinose, radish sugar, and glucosamine are accumulated in low-K + stress, and are also detected in plants under P or cold stress ( Cook et al., 2004 ; Ding et al., 2021 ; Xiong et al., 2022 ). Flavonoids and phenols are major secondary metabolites involved in plant immunity ( Wang and Wu, 2013 ).…”

“…These studies have identified transcription factors and genes involved in metabolic pathways (including those encoding carbohydrates, plant hormones, and kinases) that play indispensable roles in maintaining plant growth under K + deficiency ( Hyun et al., 2014 ; Zhao et al., 2018 ; Yang et al., 2021 ). Seedlings can regulate mineral nutrient absorption via the roots ( Bari et al., 2006 ; Tabata et al., 2014 ; Xiong et al., 2022 ). High-affinity K + transporters regulate K + uptake by cotton roots during K + deficiency ( Wang et al., 2019 ).…”

“…Integrated transcriptomic and metabolomic methods are increasingly being applied to reveal molecular mechanisms of environmental stress resistance in different crops based on genetic, physiological, and morphological data ( Bowne et al., 2011 ). This approach has led to the unraveling of the tolerance mechanism of wild soybean seedling roots to low-N stress ( Liu et al., 2020 ), identification of candidate genes possibly involved in oat adaptation to P deficiency ( Wang et al., 2018 ), elucidation of the response of rice carbon and N metabolism to high N ( Xin et al., 2019 ), understanding metabolic changes caused by regulation of P utilization efficiency in rice leaves ( Wasaki et al., 2003 ), regulation of phosphorylated metabolite metabolism in soybean roots in response to P deficiency ( Mo et al., 2019 ), effect of N deficiency on wheat grains during the medium filling stage ( Wang et al., 2021 ), response mechanisms of apple to different P stresses ( Sun et al., 2021 ), regulatory mechanisms of primary and secondary metabolism of peanut roots under N deficiency stress ( Yang et al., 2022 ), and the transcriptional and metabolic responses of maize buds to long-term K + deficiency ( Xiong et al., 2022 ).…”