Pepper(Capsicum annuum)xylogen-like arabinogalactan protein(XYLP)1 and XYLP2 promote synthesis of lignin during stem development to cope with stresses

Pepper stems exhibit a high level of strength and lignin deposition to support plant growth,which direct the cultivation style without binding sticks or scaffolding.However,regulation of lignin synthesis and accumulation in pepper stem has not been extensively studied.Herein,we first investigated the pepper stem developmental process and confirmed that increasing lignin accumulation occurs during stem growth.We then performed genome-wide identification and characterization of xylogen-like arabinogalactan protein(XYLP)family members and obtained 10,22,and 19 XYLPs in pepper,tomato,and potato respectively.Evaluation of the phylogenetic relationship among the identified XYLPs suggested that these proteins are conserved in Solanaceae.Thereafter,we analyzed the 10 CanXYLP genes and observed that these genes exhibit differential expressing patterns at different stages of pepper stem development.Among these genes,two XYLPs,namely CanXYLP1 and CanXYLP2,exhibited an increased expression pattern and a strong correlation with lignin accumulation in pepper stem.We further found that CanXYLP1 and CanXYLP2 play a role in pepper stem lignification by positively regulating the lignin synthesis pathway genes in pepper,and the CanXYLP1/2-silenced plants displayed a blocked lignification phenotype.Finally,we confirmed that CanXYLP1/2 expression is upregulated in response to some abiotic and biotic signals,suggesting that these two genes enhance the tolerance of pepper stem to unfavorable conditions.These results contribute to our understanding of the molecular mechanism controlling pepper stem lignification,and the relationship between the lignin content of pepper stem and XYLPs.

The current phosphate recycling situation in China and Germany:a comparative review

Phosphorus(P)is an indispensable element for organisms but the primary source of P-mineral phosphate resources-are non-renewable.Agricultural production has a high demand for fossil phosphate resources,but the resulting phosphate-rich residues are lack of management.This leads to rapid reserves depletion and severe phosphate pollution risks.One sustainable way is to reuse the phosphate dispersed in various residues such as sewage sludge and livestock manure.Diverse techniques have emerged to recover phosphate from wastes to close the phosphate cycle.While it is a global issue,the regional situations regarding potential phosphate scarcity and its management differ strongly.China is rich in phosphate resources,but over-exploitation has greatly increased the risk of phosphate rocks depletion,while in Germany the P resources depend on imports,but there is commitment to keep a balance between import and utilization.This had led to great differences in the way the two countries deal with the"re-use"of phosphate in waste.China is now in a transition phase from the simple terminal pollution control to"waste"reuse and nutrient resources recycling.One sign of this tendency is the mandatory garbage classification and preparation for further processing and recycling.This was first implemented in Shanghai in 2019,whereas Germany has been following the legal framework for waste management since the 19 th century.There are a series of laws to control the nutrient loss from municipal and agricultural activities,as for instance with sewage sludge ordinance and fertilizer legislation.Many of these laws have been newly revised recently.Sewage sludge cannot be directly utilized on farmland as organic fertilizer any more.Alternatively,phosphate and other nutrients should be recovered from sewage sludge.Advanced phosphate recovery technologies and related nutrient recycling schemes are proceeding.This review summarizes the current situation of phosphate-containing residues management and phosphate reuse in China and Germany.The state legislation and policies,which would affect the phosphate recycling concept are presented as well.As there are various kinds of phosphate-containing residues,different phosphate recovery technologies can be applied.Those technologies are discussed from their mechanism and suitability.